Missing period help!!

Hey

Im 16 years old and started my first period in February this year.

I havent had my period since july. In mid august i had unprotected sex for 3 mins.

Now i havent gotten my period at all. Ive taken 3 pregnancy tests and they have all been negative. I have no symptoms, i havent gained any weight, and I dont feel pregnant.

If i was pregnant i would be at 14 weeks. I had a blood test done 2 weeks ago but i still havent gotten the results.

Ive been scared shitless about this since august. At the end of august i had about 3 days of red/brown spotting. I was also overseas at the time when i got the spotting.

In july I had a really light period. Like super light. And im quite skinny. I weigh 45 kg and am 5.5 tall

Hopefully im not pregnant.