I totally understand. A few years ago, I started abusing amphetamine and MAMA along with many other drugs. I was shooting up speed nearly every day for months and as time went on, my anxiety was getting worse and worse. I was constantly worried and freaking out about my heart and dying from a heart attack or heart failure. I would check my heart rate probably over 15x a day and be obsessed with my BP. Then I started to constantly feel my heart beating through my chest which made me super anxious. I couldn't sleep because of it and I felt so certain that my heart was damaged. I thought my heart was beating way too hard (cause I always felt it) and because I was always focused on it, my anxiety got even worse. I refused to exert myself, I would get panic attacks, I would get palpitations and now I know it was caused by anxiety but during that time I just thought my heart was fucked. So it was a vicious cycle of anxiety and symptoms from anxiety but I thought it was just something wrong with my heart so more anxiety and so on and so forth.
I realized it was all in my head and I was driving myself crazy. I stopped using any stimulants COMPLETELY. I didn't even smoke weed because that caused an increase in my heart rate which caused anxiety/paranoia. I had great support from my husband, I visited the doctor to ensure myself that my heart was fine and I was healthy, I slowly began to do things that had previously made me anxious and I kept reminding myself that I was fine and it was all in my head.
It's been about 3 years since this all began and today I am doing SO much better. I won't lie though, I still get anxious about it and still avoid stimulants and any drugs that would cause anxiety (sadly, it's quite a few Lol). But now I have Bo problem sleeping, exerting myself, I no longer experience panic attacks about it and I understand that I am physically healthy and it's all mental. I am not cured, but it no longer seriously negatively impacts my life.
So, my suggestion is to stay clear of any drugs that would increase your symptoms and/or anxiety. That doesn't mean you can't do other drugs unless they all increase your anxiety and/or symptoms. For me, I still heavily abused opiates, benzos and other downers. As a matter of fact, opiates and benzos actually made me feel as though they "helped my heart". I know obviously they didn't, they just covered up my symptoms (increased heart rate, feeling my heart, etc) and decreased my anxiety. This doesn't mean I suggest you abuse opiates or benzos to help you cause let's be real, that's pretty stupid. I'm just telling you my honest experience and letting you know this doesn't mean you have to become Sober Sally if you don't want to. This doesn't mean you can't ever do stimulants or MDMA or other drugs that make you feel bad ever again. I mean, I highly suggest you stay away from them forever, but if you don't want to, at least just give yourself time to heal.
Good Luck!