Am I actually pregnant???

I have taken a pregnancy test, and yes it did turn positive. But the thing is I left it for a while because I forgot about it. I thought I might have been but the first few days of March I had a 1-2day super light period. Almost to light to call a period. I'm only saying this because I've never had a short period, and it's really heavy the second day. I did take a second one but nothing showed up. Ever since a bit before Valentine's Day I've felt off, and been nauseous most of the time. I'm scared I truly am though because I'm only 15, and my mom honestly thinks I'm a virgin. And because I didn't have any thought I could be pregnant, I didn't make very good choices at all up until about a week ago. Please tell me there's a chance I'm not pregnant and just sick????