Hi, im a teenager and I had sex 4months ago using the withdrawal method. I took a pregnancy test and it was negitive. My periods used to be 7 full days and heavy but 3 months ago it became lighter and only last for three days. Some of my symptoms are back pain, horrible headaches, i gained weight ,clothes are to tight, nausea, dizziness,irritability, food cravings for food i never liked, my boobs are to big for my bra and to sensitive to put a bra on anymore, im always hungry even after eating a HUGE meal. There is more but from this information do you think theres a chance i might be pregnant