What Causes Irregular Periods,bloating Of Stomach,heart Burns And Headache?

i got off birth control about 9 months ago and have been trying to get pregnant. i have taken god knows how many home urine tests and they have came back negative except for two which have came back really light like clear but a visible line. i have had irregular periods for the past 4 months and last wk i bled for 2 days and it was jus spotting. yesterday i started spotting and today i am not. my stomach has been getting bigger and i have been getting frequent but slight headaches that dont last very long. i have been to the doctor and had two blood tests done that was in jan and feb and they both came back negative, i feel pregnant. about 4 months ago i had really bad heart burn and now i dont have it anymore. i constantly go to the bathroom and sometimes feel sick to my stomach.. could i be pregnant? what should i do?