What Causes Heart Palpitations While Sleeping?

Good Morning, I hope you can help. I am 22 years old and was diagnosed with depression from the age of 12. I have recently gone through a bad break-up with my partner of two years. The relationship became mentally abusive when he was diagnosed with epilepsy last year and he became addicted to drugs bought online. The last 6 months have really taken it out of me, the stress it caused me and my loved ones was making me lose my hair and seemed to trigger an eating disorder in me. Since the break up, my eating has definitely improved but I am now struggling to sleep. Whenever I get in to bed and try to relax, I get heart palpitations that are impossible to ignore. I can feel my heart eat in my face and throat. I try deep breathing to send me off but it only minorly subdues the symptoms. I also twitch some nights, it feels like little jolts mainly in my head and legs. I have hardly gotten more than 2 hours sleep a night in the last 5 weeks. I think this is caused by stress but obviously I m scared that it could be something more serious. I would be very grateful for any advice you can give.