Hey, I'm not a single parent, but I've had 3 pregnancies(2 children). My first pregnancy...I was about 4.5-5 weeks along when I finally took a test. I had noticed that my period was late, that I was nauseus throughout the day, but otherwise, nothing. I waited a few days, and finally took a test. It was positive. I miscarried at 14 weeks, though. With my second pregnancy, I knew the morning of the day after my missed period. For example, I was supposed to start on Thursday, I tested Friday morning and it was positive. I was nauseus all of Thursday night, but the sick feeling would go away if I ate something. I had a baby girl 39 weeks later. With my third pregnancy I also knew the day after my missed period. I was nauseus the night before, so I tested the next morning and it was positive. I had a baby girl 42 weeks later. :P My girls are 12 months and 3 weeks apart.
Try taking a test...you can get them cheap at teh dollar store and they work just as good as the wal mart ones.