100-120 is not a seriously bad heart rate, especially because of cannabis/ect... While it's fine that you went to the emergency room (and no, they're not allowed to call the cops on you if you say you smoke pot), you really should sort out the anxiety and depression in your life. It can be really difficult, but it's worth it. I used to have anxiety attacks with only the physical feelings- butterflies in my stomach, adrenaline rushes throughout my body, and increased heart rate, while feeling no anxiety at all. It's a subconscious thing, I think?

Try to get everything sorted out, and I hope all goes well with ya