Hi Yael,
It sounds like you may have the same as I did. Try and get into your dr ASAP as I let mine go for a few days and when it burst it was like a huge blood stained puss and it really frightened me as I didn't know at the time what was going on. If you can get on to the antibiotics quickly you may be able to save this from happening.

I hope all goes well for you.

Sharon