not sleeping

I am getting so sick of this to the point I just want to cry. This is the 2nd time this week this has happened and it's been an ongoing problem for a while. I can sleep 16+ hours and wake up at like 9 am and still be tired after being up for 40+ hours and then it starts all over again. I wake up early can't sleep at night and it's really fucking with me mentally. The sleeping medicine just makes me wake up groggy or I sleep so long on it that my SO starts to worry. I've tried lowering the dosage as suggested by my doctor but it doesn't help. I just want to have a normal sleep schedule. Because even after sleeping for more than 16 hours I wake up and I'm a total bitch. It's currently 4:25 and I've been up since 9 am yesterday, I'm tired but when I try to lay down I can't sleep. It's either I sleep too much or not at all. It's effecting me being able to work and not be dead tired all the time. I've have blood work done multiple times to check my iron and thyroid and everything always comes back perfect. What is so wrong with my body that I can't sleep 😭😭