OK, ladies, I'm having yet another issue today- I swear,this cycle is just being horrible to me- I'm really hoping it's worth it!

So I went to pee about an hour and a half ago and there was a little bit of blood in my underwear- and a little string of red in my CM. I'm only 4 DPO so I don't think it can be IB- can it??? I wanted to call my doctor but it's 10:30 at night and apparently they aren't open on Fridays- ugh! There's a number to call for emergencies but I really don't think this counts. Oh, I'm also having some mild cramps, almost like AF,but not bad. I REALLY don't think I can be already spotting for AF, right? I mean, geez! Do you think it could just be irritation? We haven't DTD though since O day so not sure. I'm just confused and feel like crying, but of course I can't because I'm at work! Any input would be awesome! Thanks ladies!
BTW, earlier today and last night I actually had yellow CM- I have no idea what's going on!