I get bad stomach pains every month, so I'm thinking I'm starting my period, but then I don't :\

I feel fine and I'm not pregnant.
I'm usually late about 3-6 days but that's normal for me
But not having my period for 3 months is worrying me now
I can't see the doctors atm because I've only just moved here and I have to register with them ¬__¬ :\
So heeeelp...
Thanks