Advice please? Worried !

So I'm 4 weeks pregnant today. As I wiped there was blood on the tissue slightly (spotting) so I put a tampon up to pull out to see what "is up there" to see this. It's old blood and minor but I can't help but worry!! Still time for implantation bleed? I've been having positive tests for 5 days now. I also took a clear blue digital this morning whcih was still saying 1-2 (I expected 2-3 But I'm not to hung up on that).

The last few days I've been very sick. Today...nothing. I've been fine. Which concerns me.