Stomach tightening , increase in stomach

My friend is experiencing a abdominal tightening in her stomach. She is feeling dizziness ,with some chills from last two days she is saying that her abdominal has increase.she has 2 or 3 acne on her skin also.she also have some burning sensation in her urine. She is having sex with her boyfriend on 6 may night and just two days before her period.then she gets bleeding like period on 8th may which remains upto 10 may as normal period.is this a period or anything else could there is any chance of pregnancy.she didn't have any sex after or before this in period of 45 days almost. And she gets her period on time always i.e. on 8 or 9 th of every month. Please specify the reason for above problems. What % chance of pregnancy was their.