Please help!!!

My husband and I have been trying to have a baby since May. My period came on July 25. I used the ovulation test strips to see if and when I ovulated. I ovulated on August 15 & August 16. I took 2 pregnancy tests and got a negative twice. I figured that it was still to early to tell. On Friday August 28 I woke up to what I thought was just spotting. Then it turned into a heavy cycle. It's now August 31 and it has almost stopped. My period wasn't due until August 31 and my cycles are irregular and never come early. My symptoms include: occasion nausea, bloating, mild cramps(nothing like period cramps), back aches, constant hunger, stomach making all kinds of noises throughout the day. Could I still be pregnant or just an early cycle all of a sudden?