Feeling worried/nervous about spotting

I'm very early on. I have been feeling extra tired and irritable, have sore boobs, and have been abnormally gassy. I have also been feeling period like cramps off and on for about a week (since before I knew I was pregnant). This morning I went to the bathroom and there was a very small amount of watery brownish/pink spotting on the tp?? Is this normal? Should I be worried? I know this can happen as implantation spotting.....but aren't I beyond that point now since I had very very clear positive pregnancy tests 3 days ago? I thought a hpt wouldn't be positive until a few days AFTER implantation?

How far along are you? Implantation has already occurred, but it could be some residual spotting. Have you had sex recently?

No sex recently. I am only 3 weeks and 6 days. Very early so I'm feeling pretty nervous. It wasn't a lot at all....but it was enough that I could notice it.