Spotting + positive test... am I just going to miscarry again!

I have been trying for 15 months. Miscarried last Aug.

I have been spotting on and off for over a week. Small amounts of brown blood. Yesterday I did an early test and It came back 'Positive'. Yay!

Although now I'm worried I am just going to miscarriage over. I've read a number of things online... from implantation bleeding should only last 2 days, to it can last weeks?!

I know no one can tell me what's going to happen but has anyone experienced this and not miscarried?!