I'm going to say, first off, that I might not be the most active member, because I joined mostly to ask this question (an hour's worth of googling didn't turn up meaningful answer).
I'm pretty sure I've pulled an abdominal muscle, if I keep doing sit-ups will it get worse? I've already taken 2 days off, I need to get back ASAP.
What did you do to possibly pull your abdominal muscle? I would recommend that you chill out on the sit ups for now and take more time off. Perhaps focus on exercising some different muscle groups, give it a chance to heal and then get back to your normal routine.
I am no professional, but it could possibly make it worse or take it longer to heal if you are not easy on it.
Just my 2 cents friend! and welcome!