Am I Pregnant or what is going on with me and when should I take another test?

Patient: Hi,I am 28 years old. I have been on birth control pills for about 5 years. I had intercorse with my boyfriend without a condom on Dec. 23 and on the 25. I lost my birth control pack so I did not take a pill on the 26th, 27th or the 28th. On the 28th I had sex with him again without a condom and by the time we where done I had started bleeding just a few spots on the bed, which had never happened before and my next period was not supose to start until January 7th and my periods have always been very regular. I continued to bleed the next 3 days very heavy bright red blood and I am not a heavy bleeder. Then on the 4 day I had light pinkish color blood and small amounts then by the end of the day a few drops of brownish blood. Then the next day I had a gush of bright red blood come out about a fourth of a cup amount. then it went back to light pink small amounts then nothing for the rest of the night. The next day brownish small drops. Today I had another gush of bright red blood early in the day. Then I whiped later and it was the pinkish color again. I took a home pregnancy test today and it was negative, but I also know it could be too early to tell. Could I be pregnant and when should I take another test? Also, my normal periods are 3 to 4 days long, and I have been bleeding like this for a week if it continues tomorrow. Pleas help, I am confused and scared.