What Causes Nausea With Constipation After Stopping Birth Control Pills?

Hello , I am 14 years old and for the past month I ve felt very weird . I ve had nausea at night , plus I ve been going to bed AND waking up hungry even if I ate dinner , I ve been extremely tired so I thought I needed more sleep but that hasn t seemed to help , I bruise a lot easier and I m having bad mood swings , I ve also been constipated but now I have diarrhea, I m having chest pains... A lot more and hip pain , today I had a bad headache . I ve been on birth control for awhile but I needed a new pack but never got it and was off for about two weeks , on the 3rd day of NOT taking the pill I had unprotected sex with my boyfriend ... Could I be pregnant or is a lot of it because of hormones and teenage things I had unprotected sex June 20th and it s not July 14th