For the most part, the majority concensus on the boards seems to be that there is never really any reason to eat lower than 1200 cals/day: and many people (myself included) feel that even 1200 is too low for most people.
I don't want to tell you what to do, of course, because I'm no nutritionist or doctor, but if I was 5'5" and exercising the amount you state, I'd start eating at about 1500-1600 cals/day, wait 2 or 3 weeks, the re-evaluate based on how many pounds I've lost.
If you try to starve yourself into weight loss, you are going to stand a very strong chance of burning out and quitting completely. Not only that, but with the exercise you'll need the calories and nutrition to help build and tone muscle and prevent injury.
I'm sure you'll get other advice as well, but this is where I would have started.
Good luck. You can do this!