Yeah AnnaB, i totally know how you feel.
I had a m/c last year, and this pregnancy is a real rollercoaster of fears. Every twinge, ache, etc, gets me running to the loo or crying because i think it's all going wrong! Even today, i have some mild twinges, so my instant assumption is somethings wrong (rather than that my peanut is trying to grow bigger!).
Its totally normal. I've found keeping a pregnancy diary is helping quite a bit. Only started it last week, but i write down everything i eat (to help work out what stops nausea) but also every symptom i'm getting. it means i've started seeing a pattern of things, so i now know i get twinges most evenings, and they're gone by the morning, so it's all normal. Give it a try. Makes you feel a bit more sane and in control of whats going on...