Hello Devon,
Well, I am not pre-menopausal, but I do get what you are talking about. Sometimes my heart beats so fast it is crazy and it just won't calm down! And it kinda skips beats and thumps and flutters. I find that cutting out chocolate and caffeine helped. Also doing things to help my anxiety stay lower helps too because theese symptoms are worse thehigher my anxiety is. So relaxation, exercise, breathing exercise all help a lot.
I walk a lot. U sually an hour a day 5-7 days a week. I find it helps lower my physical tension by just so much.I find I have less heart flutters and thumps and less fast hearbeat since I do.
So hang in there, this can get better.
If it persists and it is freaking you out, have it checked out tho. I did and once I knew for sure I was ok, I felt a lot calmer and that helped too :P But that is just me :)
Anyway, Just wanted to say that in my experience the exercise really does work :)
-Diva