Hi A.!
First of all, BREATHE. You will be okay. I know what it's like to be in the throes of OCD/anxiety, and to feel like NO ONE knows what it's like. You are not alone.
I have had OCD/anxiety my whole life, and they usually manifest themselves in repetitive thought cycles that drive me nuts. Lately, when I get stressed (my DD is 6 1/2 months), it manifests as health anxiety (a nice way of saying I am a crazy hypochondriac at times). Everyone who has replied has mentioned some great ideas. Here are mine:
--Medication. I guarantee there is something that is right for you. I am on 50 mg of Zoloft. It works, and is one of the safest SSRIs for breastfeeding moms. I have yucky side effects when I go on and off of it though. SSRIs affect everyone differently, so there may be a better one for you.
--Exercise. I cannot tell you how important this is. I have always loved to exercise -- volleyball, long runs, weightlifting, and if if I get too busy to do those things, there is a direct correlation to anxiety. You don't have to be that gung-ho, either ... walking or light yoga will help!
--Other activities. I work full-time (partly at home, partly in the office), so I am able to immerse myself in something other than mommyhood. But there are other things I like to do, like reading, cross-stitching, exercise, watching movies, etc. Find those things that you like to do apart from your child. Use those naptimes... once you are focusing on something you enjoy OTHER than your child or your anxiety, you will feel a little bit better.
Good luck!
J.