Could i be pregnant? PLEASE HELP !!?

i've had some problems with taking the pill so i stopped taking it. My periods never used to be regular but after stopping the pill i'm usually just one day in advance on my period or a day late but nothing major.Then i was one week late on my period (should have came been on the 8th May) and then on the 12th of may i got a brown discharge that lasted for about 3-4 days then i took a pregnancy test and it was negative! I still hadn't had my period i began to feel sick all the time and no be able to eat alot so i eat little and often. I was due on my period on the 4th of July but there is still no sign of it !! it's nowthe 16th of july and still no sign i feel sick constantly,when i drink fizzy pop from the bottle it tastes like metal !! i've been craving food but can't eat alot at once i am really retaining fluid all over.my breats have become enlarged and they tingle and hurt sometimes , my nipples have darkened and are funny shapes. my lower stomach has become bloated and a little hard. I get very tired very quickly !! but i have done 4 home pregnancy tests and they are all NEGATIVE !! what is happening ? i'm due on my period on the 1st of july so if i am pregnant how far gone would i be ? My last period was on the 9th of April and it was very very light and only lasted for a day and a half - 2 days !! SOMEONE PLEASE HELP !!