Hi Emilee,

It is pretty common and if you find it last longer, like 1-2 weeks before your period, and interferes with your functioning in life, including relationships, you could have pmdd. One treatment is with sarafem (prozac) that you take 2 weeks before your period and it works, I have PMDD.
But from what you have wrote it seems like PMS for you now. I like the idea of dark chocolate. remember you can put it in a shake or something if you don't like it much. Good luck