Ive gained weight dramatically in a month and a few weeks and my friends had been telling me that i am gaining?

weight like a prego girl but im on bcp called seasonique i been on it since jan 2011 and around may was when i started to gain weight. i have taken pregnancy tests like 5 and all are negative i feel weird lately and ive had my period since begining of june and till today june 30 i still have it. it has been weird it goes away then comes back. it sometimes is red and then brown then both at the same time. i feel pain everywhere on my body i been having this weird cramp feeling on my right foot the bottom and its worst when i walk. i want to know if it might be cause of the birth control pills or can it be that im prego. i got an appt on july 7 for an ultrasound due to alot of abdominal pain. i also go diagnosed with irregular bowel syndrom but and x ray has been made and it showed gas in my stomach so i got refered to a gastroenterologist which i go to tommorow as well. i have so much hitting me at once help me.