Can an 11 year old girl get pregnant if she has not started her period at all? I am afraid that has happened to me. I know I sinned and I need a pregnancy test. I have not told my mom yet. I have all the signs. My friend's mom and she know about it. I think they will get me a pregnancy test soon.
Yes, it can happen. A female releases an egg two weeks before her next period. Thus, if sex takes place just before your first period, an egg could be present and you could end up pregnant. The odds are low, but it isn't impossible. The symptoms you are experiencing can just as likely be due to stress and worry and may not be due to pregnancy.
But it isn't just pregnancy you should be concerned about. Whoever the guy is, he has likely had sex with other people. That means you have a greater risk of being exposed to a sexually transmitted disease. Some of these disease don't show symptoms for a while, if at all. Therefore, you need to see a doctor about this as well.
As hard as it will be to do, you do need to tell your mother.
I don't know your relationship with the boy, but it needs to end. He is just using you for his pleasure and he is putting your life at risk. Pregnancy in young girls is far riskier than with women in their twenties.
Finally, you need change your life. The direction you are heading is not healthy for your soul. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4).