Maybe Pregnant or Miscarriage?

Sorry if this isn’t the right place to post. I am 18, currently on vienva birth control and have been or a few months. I am also quite overweight. I’ve been taking vienva everyday, but I missed a day or two in the last month and took it late a few times last month as we were moving everything was a mess. I took a pregnancy test this morning and came back with a positive, so I drank some water and went to the store to get another test. Took that test when I got home and it said negative. Why I took a test in the first place idk just a feeling. Both tests had the same sensitivity level too. I’m not on any fertility drugs or trying to get pregnant either. Anyways, I was bleeding a few days ago some brownish dark red blood so I am confused. Sorry I don’t have a picture to show but what do y’all think? What should I do? Sorry I know it was long but I just wanna hear anyone’s thoughts. I got a negative 2hrs after getting a positive on a different test. Thank you!