Am I pregnant?

It's a long story but bear with me - I had my period beginning 29 june and my cycle is usually 34-36 days. But I had some heavy spotting (never had it before) from 27-29 july, as well as nausea and fatigue the week before. Did a pregnancy test on 30 Aug, came back negative, did another on 1st September came back positive. Tests were coming back positive until about 12 Aug. Had a blood test done to check if I was pregnant on the 18th and it came back negative. Then again I had some heavy-mild spotted from 20th to 22nd Aug. No period since. Had nausea and fatigue again this week so I did another pregnancy test today. No I can't tell if it's positive or not. And if it is - how many weeks am I?