Bleeding at 3 weeks???

So a few days ago I impatiently took a pregnancy test and I got a faint faint positive line. But I waited to get excited cause a few months ago I experienced a miscarriage. Well I waited another day and took another test and the same thing happened so I'm thinking there's no way I'm not pregnant right? Well I woke up this morning and when I wiped it looks like my period so now I'm freaking out; I had a friend that had her "period" for 3 months before finding out she was pregnant. Could that be happening to me? She also said that if it lasts it's normal days I could still be pregnant; any suggestions or has anyone else gone through this??