Pregnant or not? i need answers fast. please.

Hi. I'm a teen so thats says that my period is irregular but not going to say my age since most people judge. me and my fiance have unprotected sex and use the pull out method (most of the time). last month i had my period at the very beginning of the month then at the end of the month i "bleed" for about 4 to 5 days but it was pinkish-redish. no brown. my normal period is extremely heavy and painful. this was neither, i had an uncomfortable feeling most the time and sometimes a cramp like thing. i went to the doctor and they gave me an ultrasound and i think a pee test and told me it was just stress. i believed that and went on with my life. i would of only been about a week or 2 i suspect and your supposed to be like 4 to 7 weeks to tell on an ultrasound. now its the end of the next month and i have and any symptoms of my period or anything. i have gained 2 to 4 pounds considering it changes. im extremely tired during the day so i lay around and watch tv then at night i stay up pretty late. but last night i went to the park with my fiance and his friend and moved around alot and i was extremely tired. im hungry alot. i wake up in the middle of the night straving and my fiance says im kinda moody. oh and i took 2 at home equate brand pregnacy test while i was bleeding and it was void. it didnt show up postive or negative. i might not be pregnant but if anyone could help it would be amazing.