Can't get past VIBRATIONS!!

I’ve been practicing astral travel for quite some time now, and im able to get myself in a deep enough state of relaxation to the point its just before falling asleep. Then i begin to feel the vibrations or sensations through my body and sometimes my heart rate increases, but then when i try to separate my body the vibrations stop and i start to lose my concentration. So is there any particular way or suggestions i can get beyond the vibrations and actually separate myself into astral projection?

Here is some extra info...

- I try to astral project at night, and sleep during day in order to stay awake at night.
- When I try to astral project, I relax completely so that I just cant possibly relax more.
- I sometimes open my eyes a bit and see some weird stuff, such as shapes (triangles, squares, stars flying around), I also see other weird stuff that Im sure are not there in reality
- After I fail to astral project I fall asleep (on purpose because Im tired of relaxing, I just want to sleep normally) and get some weird dreams that I never had before
- I try all this in a bunk bed, I sleep at the top (maybe this has something to do with the problem)
- I started to do all this about 2-3 months ago

I hope to hear an answer soon, this is really important to me.

Thank you!