Very short AF, advice needed!

Last month AF was 6 days long. This month, AF was kinda late, was due on 6/5, only had very light spotting that day and didn't et anything til 6/6 & 6/7, it wasn't that heavy at all and was very dark red and brown. Today I had light spotting this morning and it's been getting lighter thru-out the day. I've also been extremely tired this past weekend, had to even take naps. I've been really nauseous all day today, and nothing is really helping it go away. I have a 29-day cycle and I ovulate on CD 20, so could I possibly be pregnant and maybe this is just early pregnancy bleeding? Any advice will help!!!