Very light spotting, 4 days late as of today?

Could this be my period? It's four days late, I haven't really been stressed and didn't even question being pregnant until my second day being late on my period, now today I'm having very very light pink/brown a spotting, doesn't even fill a panty liner, it last maybe an hour and goes away and came back. Could I be pregnant? My period usually isn't irregular and it never starts out like this, usually it's just straight to my normal heavy flow..