Can't get back to sleep

im fairly new to the whole lucid dreams thing and recently got my recall to about 3 dreams a night. about a week ago i had a really short lucid where i realized i was dreaming then instantly woke up. since then my dream recall has gone way down and the vividness has decreased. i havent had any ld since.
My main problem is that i wake up naturally around 4, dont remember any dream, but then it takes me around an hour and a half to fall back asleep, even if im not trying WILD. Does anyone have any tips or tricks to fall back asleep. im really interested in lucid dreaming but this being up for an hour and a half at 4 in the morning is very disillusioning, and it happens consistently every night now. any advice? Thanks

If you're not getting enough sleep you'll start to suffer reduced REM periods anyway which might be why you are having trouble remembering dreams.

Meditation is a good way to relax yourself and get your mind and body in a state where you can drift off to sleep. In particular meditations that focus on your breathing work best. If you try to breath as slowly and deeply as possible whilst laying still, your body will relax more. Particulary focus on the out breath, the slower and longer you can make this the more relxaed and sleepy you'll feel.