I am 13. Is my period too heavy?

I am 13. I started my first period about a year ago. My periods have never been overly heavy, but the last few I have had have been extremely heavy for at least 2 days. They are so heavy that when I stand up after sitting for a while, it feels like a river is coming out. My periods tend to last about 5 days, but after those 5 days, I won't bleed for a day, then a little bit of blood will come out. It is extemely uncomfortable because I feel like I never really know for sure when my period is over or not. This will continue for up to 5 days. I feel like I would be more comfortable wearing a tampon, but my mom doesn't buy them, and I am too shy to ask. I am worried that there is something wrong with me, or that I might be losing too much blood. My mom is going through something similar. She has a fibroid, however, and may need a hysterectomy. I am sooooo worried I might have something like that, or worse. Please tell me what to do!!!