Pregnant?

Autumn • mommy of one who doesn't enjoy birth control.
This is a bit of a hard to explain situation. The other day I posted about a 3 day late period, which was a first but I ended up deleting in when I got my "period" on Friday. The odd thing about it is that I usually have 5-6 day periods but this time around it wasn't even 3 days? It started early Friday around 3am at a normal flow. Saturday it lightened up a bit, and by Sunday I had just some minimal spotting. I did take a test the day before the bleeding began, which came up negative. But the thing is that I have very short cycles, around 3.5 weeks. So if I would have conceived during ovulation I'd only be around 3 weeks pregnant, too early for the test to pick up any hCG levels. And the weirdest thing is that my period is now over but I'm still bloated, cramped, and a bit dizzy. No appetite, minor nausea. Has anyone had anything like this before? Can I be pregnant or am I crazy?