For me, I got nauseated and lost my appetite. I also felt like I had a really bad case of PMS, but I didn’t start. Finally, I threw up one morning, and realized there might be something to it.
Even so, I didn’t “believe” I was pregnant until I saw the ultrasound.
Robin
It’s not weird or uncommon. I have had preg symptoms a week before even finding out I was pregnant. I also cramped quite a bit during implantation, which made it seem like my period was imminent.
There are a few tests on the market that test for hcg (the hormone that pregnant women release into their urine) in very small amounts, so you can test even before your period is due. I think the earliest you can test positive is 10 days post ovulation, or about 4 days before your period would be due. A google search would probably turn up the brands that test the smallest amounts of hcg.
According to an ex-GF, her BF at the time was able to tell she was pregnant by a change in her taste, if you know what I mean. Go tell Mr. Jar to give you a long, slow pregnancy test. 
May the result be whatever you prefer it to be.