I am planning on doing home pregnancy tests but they are not always accurate

My boyfriend and I had sex the weekend of my birthday (3-16). The 18th I started feeling yucky and tired and this lasted about 2 days. I am on the pill and I take it every day but i take it at different times so the timing is not consistent. Thursday I was not feeling good and did not want to eat or drink but thought maybe I was dehydrated so I forced myself to drink some water and this made me nauseous, just the feeling of the water running down my throat. I do feel like I may be bloated but my period is coming in a few days. And also we have been eating out a lot recently and I have been eating a lot of fatty and definitely unhealthy foods. I am cramping which happens when I get my period but it sometimes happens before my period. I am planning on doing home pregnancy tests but they are not always accurate. My mom doesn't know him and I are having sex so I really don't want her to know. I am so scared!