im 18 years old and my boyfriend is 44 yrs old..we've been having unprotected sex for over a year and i still havent gotten pregnant..so i missed a full period for a whole month and then it came on the next month..during the month i missed my period i was feeling some symtoms like:sore breasts,tiredness,bloating and cramps..i took 2 preganancy test they both were negative..can i still be pregnant?