Coping with Nighttime Anxiety: Need Help!

How do I cope with nighttime after dealing with heightened anxiety throughout the day? I don't know if I'll be able to wind down. I was in the room during a lot of triggering conversations today (couldn't remove myself from the situation) and dealing with physical anxiety symptoms. Worst of all is that I'm dealing with these thoughts that I've messed up my life and things won't get better. I don't have much of a support system at home and can't see a doctor. How do I cope with this on my own? I would really like to sleep tonight but it's been hard and right now I just feel like a ball of anxiety, insomnia, and catastrophic thoughts.