dear Rosalie, welcome to the forum, and from what I have read it's going to very difficult to fall asleep and stay asleep, because your mind is racing so fast, always thinking about 'what if' or 'what am I going to do', and this can happen even if you aren't particularly thinking about anything, sounds peculiar, but it's not, because depression is capable of doing anything to harm or want to destroy us.
On the other hand if you do have a good nights sleep, only in terms of hours, you can still wake feeling like you have only had an hour or so of sleep.
What I suggest is that you have to try and break this same routine, like going to bed when you feel tired and not stay up until your usual bed time, all change is difficult to do, because we are creatures of habit.
Your doctor will be able to assist you with some sort of medication.
Your main goal is to achieve what and how you want to feel, so that you can get back on track. Geoff. x