Could i be pregnant?

I am 19 years old and female. Im wondering if i could be pregnant. Me and my fiance the past two months were having un-protected sex and i have not been really showing signs of pregnancy but My breasts were really tender and sensitive and i was getting sick for awhile but i have had my period the past 2 months. Although everytime i start i am having a brown mucus  like blood coming out the first day of it then there is dark red blood. and i all of a sudden have stretch marks just below my belly button and i cannot bend over without  feeling exhausted afterwards. I have also been more tired than usual as well and sorta eating more than usual as well. Im also getting more constipated too. Im really not sure what is going on and i thought i might have had a miscarriage the two days before i started cause i was at the ocean and got slammed into my fiance's back while in the water and hit my stomach really hard. But still im getting weird symptoms so im getting worried about what is going on and plus my stomach feels like its stretching as well but when i took a home pregnancy test like 4 weeks ago it came up negative. And im on my period now. so im wondering if im pregnant or if there is something else wrong?

[jelenakalaica23]

Brownish tinge or discharge in cervical mucus is almost always old blood that did not leave the uterus during your last menstrual cycle. Sometimes a brown tinge can also be associated with ovulation. It might be related to a bleeding from a ruptured follicle. Occasionally when you see a brownish tinge in your cervical mucus, it can also be the result of trauma to the cervix. This could mean either an infection or something as simple as sexual intercourse. you having strech marks may also be a sign of pregnancy the exhaustion is also one. you can not be pregnant and have your period but on the other hand bleeding while pregnant (early stages) is may be normal. but if you are saying now that you have your period it may be that you are not pregnant and the brownish color could be a result of an infection. you should go see your doctor when you get the time.