Ok So Im 16 Years Old And Im Starting To

Ok so im 16 years old and im starting to worry cause im sexually active , and i had my period on the 3rd of jan ended on the 7th , i had unprotected sex with my boyfriend on the 12 & 15 and on the 17 i bled a lil dot of blood and later on the night i started to have a real bad back pain so i went to the hospital around 4am the told me i had a bladder infection i guess i had (UTI) they gave me antibiotics and then i peed pumpkin orange but my period came in again on the 22 but on the 24 i had sex with a condom on my period but it was quick like 2 min cause i fell disgusted , and the next day my period was over i had unprotected sex on the 25 & 26 and again on the 5 & 6 of February and on the 12 and i haven't got my period i took 2 hpt and a bfn i went to the doctors to take a pregnancy test and again bfn on the 22 of February she told me to go back in 2 weeks which will be march 7 to take another urine test .... im very confused do you think the antibiotics delayed my period ? I also have a little bit of anemia and a little cholesterol .. the symptoms i have is
- always tired , im always sleeping and im very lazy ..
-mild back pain
-mild cramping at times
-mild breast pain
-mild head ache
- always having to wake up to pee which is unusual ..
- bloated
Could i be pregnant ????

Btw , my email address doesnt work can you respond another way facebook ? Lindsay bk
Email address lindsay_martinez@yahoo