doomcastirons

It's not that I'm worried but I just wanted things cleared up to find out whether or not it was normal.

I started dating my girlfriend in December and things are going more than great. She told me her period came around the end of the month but lately they have been earlier and earlier(we have beens sexually active since feb).

Anyways, she was at my house this weekend and she started crying because she couldn't find her hair elastic. I was kind of taken aback but since we tell each other everything I asked her what was wrong and she told me she was just pms'ing. She told me once she was doing the dishes and couldn't get a spot off and started crying. We both had a laugh at that one.

What I would like to know is why she has been getting her periods earlier than before(she says they have always been the same until she met me). Can emotions and being sexually active have an effect? Also, I'm pretty sure it's normal for a girl to get extremely emotional so her crying doesn't affect me too much but is it common? I know alot of girls who would get really angry during pms.

Thanks.