Implantation bleeding

Amber

OK guys I’m 28 this is my second time ever being pregnant the first time was about two years ago and it ended very quickly in a miscarriage now I just found out three days ago that I am expecting which is great news for me but I have been spotting some brownish serve not enough for a tampon or a panty liner but can anybody give me any pointers how long does implantation laugh is this normal should I be worried