Help please! ? Pregnant, maybe?!?

So, I'm curious has anyone ever actually had implantation bleeding? I know everyone's different, but if so how long/ everyone's different, but if so how long/how heavy/anything else you want to add. The reason I ask, and this is the tmi part; is I went to pee last night and wiped, and there was a bit of pink blood there, maybe about as big/as much as a nickel or quarter. Well, I've since used the restroom again, and I think I saw a teeny tiny drop but that's it. Nothing else when I wiped in between those times, and nothing on my underwear or a pantiliner. Also, normally if I start to spot my period comes fullblown the next morning. And my period isn't due until the 22nd, but it did start on the 18th last month and end on the 22nd. So, maybe it's Just hopeful thinking, and I'll still get a test if my fullblown period doesn't show, but I'm interested in hearing your implantation bleeding stories. *Since I wrote this earlier(asked on a different site) I've had some more discharge, but it's only been pink. I did have a missed miscarriage in December 2010 if that matters. Thanks.