Heart palpitations with caffeine, alcohol, and around my period?

My heart has been racing/skipping since about 9th grade. (I'm 23 right now.) We decided before that it was due to caffeine/too much sugar intake, so I stopped drinking caffeine and stopped eating excessive amounts of sugar. My heart would still occasionally skip beats, which doesn't bother me half as much as when it races. I started drinking after graduating high school and I had that time where I partied for like 6 months straight. I only noticed a couple times that it caused my heart to race. It always corrects itself with in 30 seconds-2 minutes. I had a baby 18 months ago and while I was pregnant, it seemed like my palpitations were better, rather then worse. I pretty much stopped drinking, except around special occasions or the odd time that my boyfriend wants to drink a bit. I drank with my friends whom I haven't seen altogether in 4 years on New Years Eve and the following day, my boyfriend and I were fighting, I was crying hysterically and really hung over, and my heart starting racing really fast, except this time I felt extremely dizzy, and it lasted probably 4 minutes. I went to the dr. about 2 weeks ago and they did blood work and did an EKG and said everything was normal. How is everything normal? I'm supposed to start my period any time now and both today and yesterday after exercising, sitting down for a minute, then running up the stairs to get something, my heart started racing. Both times probably 30 second episodes, but I still hate it. Should I go back to the doctor? What causes this around my period? I hate it. :( I feel like one day it's not going to be able to get it's rhythm back and kill me.