irregular cycle can i still be pregnant?

ok i have never had a normal period i started at 13 i am now 21. When my cycle would come it was heavy flow, painful, and long. Later in high school it stopped. i would maybe have a period less than 6 times a year. at 14 told me don’t worry until i am 18. At 18 the doctor said it was ok some women don’t have a period at that age. Went back at 20 they said come back in two weeks for another check up. the last year i had a constant brown discharge sometimes foul smelling. i know i should have gone to the doctor but they always say come back or i am ok.

Here is the dilemma i am kind of in a stressful living situation and i am overweight by 50lbs. factors that can effect my cycle. I had a normal period for the first time in 1 1/2 years. it went off no discharge. I had intercourse one month later no protection for a week. My boyfriend doesn’t have large amounts of ejaculation. Many times none at all. The few times he did, he pulled out.

now two weeks later i have pregnancy symptoms they include: headaches, fatigue, constipation, frequent urination(without large amounts of fluid consumption), light cramping, bloating, always wanting to cry( i usually don’t cry),when i eat i am ravenous( no weight gain though), and a white creamy discharge no odor. i have tested three times and all negative but symptoms haven't stopped and i felt nauseated on two different nights, once in the morning.

Any input will help. I do plan to go to the doctor shortly if I don’t improve.