Should I be worried

I woke up this morning - and of course being paranoid- I check my wipe. I had the slightest brown (I'm guessing old blood) mixed in with discharge. It wasn't much at all and was only that one wipe. Should I be concerned ? I had a missed miscarriage that resulted in a d and c in September. My first and only period in between that and getting pregnant again was the heaviest I ever had. Could it be old blood or old implantation bleeding? I'm 5w2d.