What Causes Pain In Lower Abdomen And Severe Sweating?

i havent had a period since feb but was on the pill till may, i whent to my doc in april coz i hadnt been on and i had pain in my lower tummy and keept feeling faint, they said it was just to do with the pill i was on, i cam off the pill at the begining of may coz i feelt that there was something not right, and then whent to see a difrent doc they just said the same thing, my simptoms are pain my lower tummy more to one side left side or in the middle lower tummy, feeling faint some times, mood swings, put on 31/2 stone since feb, sweeting a lot to the point that sweet drips off me, i have dun a pregnaciy test that turned out to be negitve