am i pregnant?

im currently taking femodene and have been for nearly 2 years, my last period was a day later and lasted 4 days and wasnt as heavy, when i finished i had sex the day after, which was the first pill of my pack. ever since ive been having hot flashes, chills, cold like symptoms,  headaches, really bad cramp in my legs so bad i cant move them, tired more in the day and waking early in the night and not falling back to sleep, feeling nauseas spontaniously, ive got a sence of feeling in my abdomen low down that my belly feels more firm and i feel spasms and my womb throbbing, ive had a child already, she is 5, had non of these symptoms and found out through a missed period at 8 weeks, it has been 15 days since i finished my bleeding and im still taking my pill, i feel pregnant but ive took 2 tests and both are neg, i know i shouldnt of been able to concieve (conceive) because of the pill but i dnt take it at the same time every day. is there a chance i could be pregnant? i also had really bad stabbing pain in my womb on the 11th day after i finshed bleeding, i havent had discharge apart from a little bit of cloudy white thick mucus when i had a wee, i feel im hungrier and have no energy like i used to. im so confused, all the symptoms, on the pill, never felt like this before on it and still negative tests.