Should I worry? Depo/spotting/prego??

I was due for my depo shot on Thursday and hubby and I had sex the evening before. Today I've been having a tiny bit of pink on the TP when I wipe, along with slight cramping.

Still haven't got my shot yet. It was the first shot this time around of being on depo, (was on it 7 years then had my daughter and back on it) I never get periods or spotting and I've never had any spotting or cramping right about the time I'm due for it...

Freaking myself out thinking it could be implantation bleeding. I'm being crazy right ?!? That's not long enough for it to be implantation right unless it was from sex the week before?

Any input appreciated!

(My daughter is 6 months and we were trying to wait til she was at least a year old to try for #2. That's the only reason I'm worried, baby #2 would be a blessing just early lol)