Never Comfortable, help please?

I just finished my second period after a D&C. However, I genuinely feel like I'm pregnant. When I lost my pregnancy in January, I wondered if this would happen, because I had two normal 'periods' while I was pregnant, one of which was less than seven days before I tested positive. I'm nauseous, my sense of smell is heightened, I'm having weird tummy troubles, and my period was strange, but heavy enough to be an actual period. I don't really think I'm pregnant, but it's like I'm never comfortable in just saying, 'Oh, here's my period. I must not be pregnant.' I can't do that after the experience with this last pregnancy. I'm probably feeling off because I'm stressed about it, and then when I tested yesterday to ease my mind, it was negative, but I got this crazy evap with color later (I had accidentally left it on the counter because my daughter was crying). Has anyone else experienced this? What did you do to get past it? I'm just tired of being paranoid, and I'm scared to even use some of my favorite essential oils because they'd interact with pregnancy. Thanks in advance!