tummy ache in early pregnancy

Jade
Im about 5 1/2 weeks pregnant and since Saturday I've been experiencing a sore tummy (mainly in evenings) all over my stomach everyday. If feels like I have an upset stomach. I'm really worried that i could be having a miscarriage, I've had miscarriages in the past. I'm not experiencing any bleeding but really worried as I seem to be having them everyday now.