BFP after a few minutes?

Courtney
Hey ladies!
I was convinced I wasn't pregnant before going on vacation 4 days ago (got a bfn before I left)
I came home and took a HPT and an OPK and checked back on it about 8 minutes after I tested (bad I know) with a wondfo. 
But the OPK had a line and the HPT defiantly had a line! It had color, but wasn't as dark as the control. 
I've had mild cramps so I was thinking AF was on her way. Has anyone heard of getting a line on both right before AF or with a BFP?!
Don't wanna get too excited, but will be testing again today. 
Ah!
Fingers crossed. Been TTC for over a year