Greeetings from a fellow empath
You might find a few hints & suggestions amongst this thread:
In all honesty, I've known I'm an empath for quite a while now, but I'm still finding out about how it all works, and how I can develop it more to my advantage - so if you find anything out yourself, would you let me know please?
I have suffered from the downsides of this ability most of my life though. How confusing is it when someone constantly acts like the life & soul of a party, yet you can pick up on heavy negatives that are going on with that person underneath the 'act' thy're putting on? Made me want to run away from people & hide from this crazy world! There's some good tips on how to help with this aspect on the above link.
Sometimes you just know things about someone or thing, without being able to pinpoint exactly how you know, or where it's come from. I also have the added problem of trying to articulate what I know....it's very frustrating at times!
One thing I will say to you though, is I think you're clear and out-of-the -blue thoughts about people are a form of mediumship called clairsentience/cognizance. It's how I communicate with spirit mostly, too. Try doing a google search for starters. You hear spirit communication as your own inner voice inside you're head - but you start to realise they're not your normal run of the mill type thoughts. The more you trust what you're getting, the better you'll become, but it sounds like you're going great guns already!
Try your hand at psychometry too - someone told me I'd be a natural at this because of my empathic/clairsentience abilites - and how right they were! If you don't know already, make sure you learn how to open up, ground & close down properly before you attempt this.