I'm almost 31 years, and it has never happened like that.
Could depend on your age? If its consistent, month after month probably not a real issue. I have always been spotty on my last two days..and I'm in late 40s.
Hi there. Might be time to make an ob/gyn appointment. If you've ruled out pregnancy (which can create something like a pseudo period), you may have a hormonal issue going on such as low progesterone. Also, any fluctuation in estrogen can cause a shorter than usual period (among other things). If you want to wait until next month to see if your period is normal, that is probably fine but if you continue to have this irregularity, I'd try to get to the root cause. Again, this is assuming you aren't pregnant.
I will say though that 3 days is considered a normal length of a period and spotting can be old blood. But this is different than your normal pattern.
Good luck!