Pregnant or paranoid?

Okay I am new to this but hopefully someone can ease my mind with some answers. I am 17 and sexually active with my boyfriend of 2 years. September 27th we had protected sex and I am also on a low dose of birth control. October 2nd I started my normal period but my spotting discharge lasted a day extra. Being worried I took a pregnancy test on the 15th which came out negative. I had been having severe back pain for a month before that so I was taken to the ER. They took a pregnancy test there which came out negative and I had a CT scan. I was admitted for 2 days and wasn't able to take my birth control so I started my period on the 18th. It was normal but heavy. I started my new pill pack that following Sunday and during that week I had forgotten to take 2 pills so I had spotting that lasted for 3 days. Ever since I have been constipated followed by bloating and gas. I took 2 pregnancy tests last week just to make sure and they both came out negative but after looking at them 3 days later, one had a faint line. I read that's an evaporation line and doesn't mean anything but me being paranoid I took 2 more tests on Monday November 11th and they both came back negative. The next day, Tuesday, I started my normal period except I have had mucus in my clots and I feel fluttering in my lower abdominal area. If I was to be pregnant my HGC levels should be high since it's almost 7 weeks but everything is negative. Could I be pregnant or am I just being paranoid? Help!