Hi lizzie, congratulations!
I have a clotting history, 2DVTs and a PE, but having had thrombophilia screens, no cause has been found.
I also did the heparin injections through my pregnancy (my first), having come off warfarin. Stings doesn't it!
Was well worth the discomfort (and worry), as I now have a happy, healthy 11mo DD. Am also planning to do the whole thing again and try for number 2.
I told people early (when I found out I was pg at 8 weeks). I was concerned about anything happening and nobody knowing I was taking the heparin, so I let everyone know just in case. The downside to this was that my pregnancy seemed to last for ever. As people don't usually let on till 3 months, people were saying 'Haven't you had that baby yet, you've been pregnant for years!'
HTH
If you have any specific concerns, post them, and I will try to address them. I also know there are others currently posting who are in the same situation as you.
If you search threads for 'clexane', I think you'll pick up some useful threads. Sorry, would do you links, but am crap at them.