I used to suffer really bad bladder infections years ago, i ended up seeing a urologist (sp) to help fix the problem (i was under his care fo almost 4 years).

Cranberry juice = awesome OR the tablets, as kelly mentioned
Ural - not sure if you can take this while pregnant or not though?
heaappps of water.

And also make sure you keep good hygene. Wash your woman bits with a handshower, to get rid of any nasties that might be lingering down there. Wipe your bum away while doing a number two. 100% cotton undies to help that area breathe. Always go to the toilet to wee after sex. Use a hand shower again after sex.

Sounds so simple and obvious i know, but i swear following these rules changed my life... I was seriously at the doctors twice a week, getting more drugs... it was hell, so painful

I hope this helps, and i hope you start feeling better asap
xx