Hey there mate, sorry to hear you're having such a difficult experience.
First thing to remember is that you're probably experiencing a bit of paranoia and anxiety because of the meth itself, which will tend to make you obsess over your fast and heavy heart beat and/or anything else that's bothering you. This happens to lots of people, and the anxiety drives them to completely overreact.
Second, unless you had a mammoth dose, your heart will probably be absolutely fine once you start to come down. It can easily cope with a long period at high levels of exertion, so even though it is beating hard, try to bear that in mind and not worry so much.
As for inducing a come down, trazodone probably won't help much while still high on meth, so don't try that. If you have no other medications, sleeping tablets, even vitamin C, then I would recommend you (a) do something calming - like slow deep breathing, putting on some chilled music, or wathcing a nice happy TV show of film; (b) have a nice hot bath or shower, which will help your blood vessels relax and feel quite soothing; and (c) try to eat and drink if you can, even if you need to use some water to chew and swallow food. This will help calm you down because it kicks in the "rest and digest" response.
But the main thing is to avoid thinking/worrying about stuff, since meth will trigger those thoughts into overdrive, and to just settle back and relax until you start to naturally come down in a few hours.