you have to differentiate premonitions and manifestations.
Premonitions are things that are meant to happen and there for out of your control.
You are connected to your loved ones. All you have is a pre-view of what is going to happen or as it happens.
Time is something here on earth, as spirits in the other realms time is not the same. There for premonitions are not the same either. Then it can be seen as something perfectly normal. It's just when we are here (on earth as humans) it is something out of the ordinary and we're trying to wrap our heads around it. One could say everything has already happened "over there". It is just that you know it before.
Have I ever figured out what would be the good of having those premonitions? No, I have not. Has it brought me pain, worries, even anxiety, confusion as in not understanding how this can be - Yes, it have.
I believe that once we have gone down a particular road that road is pre destined. Things has to run it's course. It is difficult sometimes to stand by and watch all this and knowing we are powerless to change it but not everything is up to us. It is out of your district, if you know what I mean? It is not on you just because you had a premonition to go in there and change it, you can't change it.
I've had premonitions months before, from nowhere, it would just hit me - and then it happened. My premonition, when I was a child, it was even much more so than as an adult but I did not have a word for it.
Children often blame themselves for no reason and then it stays the truth. You are way too hard on yourself. You are not causing this.
There is a huge difference between having premonitions and having accidental manifestations. For your own sake you have to learn the difference. I feel for you so I am sorry if I am coming on strong here and repeating myself.
I have seen it so many times with myself, too when I was in the relationship with the psychopath - because my level of stress, of fear was stronger I did not sleep well but on the surface everything was just dandy, just fine. What happened was that my gift(?) increased in me sensing energies and simply knowing. I was scared myself at what was happening. It hadn't been that strong since I was a child and now it was even stronger. I had had random, and as you too say accidental or it seems, but no more and no less. I would try my hardest to explain it in terms to myself that my subconscious catch up "the little things" and then presented it to my conscious and that was why it came to me as a "knowing", but truth to be told that was not enough of an explanation.
When my mind go on "high drive" so do my gifts. When my mind is in balance it means my gift are, I can then better control it. If you get your stress level down I think things will balance for you too.
I think you have high standard on yourself, demands on yourself, you think if something bad happens to someone else that is your fault and so you have failed, you come down hard on yourself for not being able to prevent it, you beat down on yourself because of it, you try your absolute hardest the next time - and yet again another failure - and the failure part is because it is not on your watch, it's not your territory, you can't do anything about it. And sometimes that is the hardest pill to swallow, to just stand by and watch it. I understand you feel very much for your family, it has come across so much how you care for them, and your empathy goes all the way - but there is a wall there, a district, that you can not pass. This is not on you.
I wish you would stop being so hard on yourself, get treatment for that if you so like or just talk to someone, talk to a psychiatrist if that will help, that can help you re-program yourself not to think like that way of yourself. That sort of change take time and it is because it has been part of your thought-program for so long. I am myself in the habit to apologize as soon as I can without thinking twice. These days I take a time-out. I have too lived with a guy who should have a medal for his instant projecting style, as that is what he has been really good at in the past, he still has to bite his tongue not to do that (It's his way of handling criticism, never mind). Did our 2 pieces of a puzzle fit? Yes, but it was on my expense, today no more. He knows too he is doing it, a defense mechanism in him. Not everything is my fault. You do it so fast and it is so in-printed in you that you are not even aware you are doing it. Just saying you could have patterns in you that you need to first of all recognize and then re-program yourself.
Then the other thing is to seek peace, calmness, in knowing what is manifestations are that, alone, and premonitions is another. Everything you have described so far are premonitions and because you are connected to your loved ones. some even get premonitions that is happening to other people they are not even connected to but will have some sort of effect later on. I think it is because time is different to us as spirits, souls and we are being then connected to our higher self, and all this is normal "over there", just not here, on earth with our time and what we have been teach on how to think about these things, that's why it can be such a struggle.
What we think, Yes, I agree, it is powerful. Our thoughts are more powerful than maybe lots of people think they are - but the incidents you have described so far, with your sister's accident, with your Dad's heart issue previously, those are pre determined incidents, it is not the result from your thought form, your manifestations. That's what I believe.
The Serenity Prayer is a prayer written by the American theologian Reinhold Niebuhr (1892–1971). ... God, grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference.
I try to think of those words sometimes, it helps :)
My heart goes out to you, and to your family - I so hope you will feel better soon.