Period or early pregnancy spotting?

I will be testing on Wednesday if this doesn't turn into a "real" period. I have an irregular cycle because of breastfeeding, so in the past 15 months the shortest was 28 days and the longest was 46 days, with an average being 34 days, but, accept for once this past Summer, my cycle usually only varies by 1-3 days, so if I have a 32 day cycle the next one might be 35 days, then I might jump back to 31 days, etc.

My husband and I had unprotected sex twice a week or so starting from the last day of my period until this past week. My period was due on day 34. It's day 43 today, and starting on day 40 I've been having barely visable to super light spotting. On day 40 and 41 I thought my period was starting, but the spotting has not increased. And I know I've only been awake for a couple hours this morning, but so far there has been less spotting today then yesterday.

Is my period just taking a reallllly long time to start? Or could this be early pregnancy spotting? I'd be somewhere between 5-7 weeks pregnant, if I am. Back in July I had that 46 day cycle, it was 2 weeks later then the 6 or 7 cycles before it, and I *knew* I was pregnant. But I wasn't. So I don't want to put a lot of money/emotion into thinking I'm pregnant this time, especially because I just decided another baby can wait so that I can focus on my career. That's why I'm not testing until Wednesday, when I'll be a week late from my longest recent cycle.