have my period and blood is dark redish brown

hello. i'm very scared at the moment. my boyfriend and i constantly have unprotected sex and maybe 4 times a day. before i saw my periods my breast became very sore and i had some sort of eczema between my breasts and i released LOADS of gas . my period came a week too early and the first 3 days were intense bleeding and heavy cramps. i took some pills (Nurofen) to calm the pain down. but i couldn't sleep for days because of sore breast. i took a pregnancy test during my periods but it was negative ( the PT was a very cheap one which had two testers in it ) i decided to keep the other tester a week later ( next week ) yesterday while i was having diner with my boyfriend and my parents, my belly suddenly hurt it was very painful i have never felt like this before i was suffocating and couldn't breath. they took me to bed and gave me some pills. 30 mins later i felt better but heavy and tired. i was urinating maybe every 5 mins. i called a nurse this morning and i was advised to do a test. the thing is i want to be sure i want to know if one of you have ever lived this kind of situation. please help

Hi, I usually have my period every 14th of the month, but this one came one week early followed with dark brown colour. What does this mean?