Hang in there, Vicky. The power of positive thought is amazing -- especially in your condition! My friend had triplets in 2000, spent most of the second half of her pregnancy on complete bed rest. Had an older child (not quite 4 then) that she couldn't even care for.
She kept saying she was going to make it to 34 weeks and have 5-pound babies. And you know what? She lasted almost EXACTLY 34 weeks and two of three were OVER 5 pounds, with the third one just under.
So keep picturing yourself with your healthy, happy, baby!
OHHHH, and you're NOT a bad mummy! If your weather has been anything like ours, it's bound to happen. I'm holding my breath hoping my crew doesn't end up with them!