“Is my girlfriend sick or potentially pregnant?”

My girlfriend and I had sex a few weeks ago. The condom slipped off after I pulled out which got us concerned as it may have partially slipped off inside and so pre-ejaculate may have touched her vagina. But I ejaculated after pulling out anyways and it was right before her expected period. So we decided not to try any birth control following this incident. (My girlfriend is not on birth control). Her period was delayed by about 5 days after this but she bled normally. Probably close to a week after her period (a few days before her expected period) we had sex again. This time we did it for a longer time than normal and she orgasmed. I didn’t ejaculate this time and was wearing a condom the whole time. Following this sex she felt dizzy and almost fainted and then she threw up her dinner. It’s been two days since then and she just had a thick and slimy pink-brown discharge that is similar to the discharge seen in implantation bleeding. She had quite a lot come out and this is abnormal. Should we be worried about an illness or could it be due to pregnancy?