anxiety?

okay so one day. a little while ago, I smoked weed, I ended up a few moments later, feeling like I HAD to go somewhere else, I felt like something kept scaring me. like a ghost was following me, I tried smoking again, same thing, so tonight, I drank, thinking, hey this couldn't be bad, won't be the same feeling, three mixers later, I felt that same way, I left my friends 0lace and went to my in laws, my fiancee and n had sex, felt worse, I got in shower, felt like I had to leave, mind you. I was at my friends drinking, we left there after I felt the anxiety attack, so right now im.on my bed at 4am trying to calm.myself down, my fiancee just tells me to quit thinking about it, what should do, I'm only 20, should I see a doctor