CheshireDing it's normal... but you should stop worrying. I don't do the gym, and never have, but my job is pretty manual, sometimes dealing with physically challenging people. I have a bad back but will still spend all day in the garden knowing I'll not be able to move the following day.... except when I'm pregnant, then I'm wary about doing everything.
The front garden needs digging over but I'm scared to do it, and last pregnancy I remember after a slightly challenging day at work I ended up in tears scared that a client might hurt the baby (totally unfounded, but it felt a huge risk at the time). I'd never given two hoots about anyone hurting me, but I was petrified of anything hurting my bump.
Try to relax though, the aches and pains you'll get are normal. Your body is growing and stretching and it's bound to cause some niggles. We're almost all past the risky 12 week stage now though.
In the next few weeks you'll start feeling bump move, which is wonderfully reassuring... and brings with it a whole new set of pains (I had horribly bruised ribs for the last few weeks last time.)
I've spent this afternoon planting some seeds with DD, and sweeping up, then needed a sit down after. :)
BB3 My first birth started like your's, except I fell of a chair and ruptured my waters. Contractions started 2 days later and DD was born 7.5 hours later.
And I agree that first poo was more scary than the birth. :o