Over Controlling Mother?

I grew up with a very controlling mother paranoid mother. Growing up I was never allowed to do anything. I was never allowed to learn to swim because she said that "the white people at the rec center would drown me because i was black". When she was not trying to control my every move she was accussing me of having . Once when i was ten years old she made me take a pregnancy test because my period was a day late. She said she knew it was late because she would count the number of days before it was suppose to start.She dragged me to the store yelled at me demanding to know who i was sleeping with. I was ten i barely knew what was nevermind knowing how to even have . I peed on the stick and of course it said that at ten years old i was not pregnant. I still get teary eyed when I think of how i had to pee on a stick while my mom yelled at me saying i was having when i wasn't.I was not allowed to wear tampons until i was 21 because she said that if i wore tampons I would start having . As i got older instead of her loosening up she got even more paranoid and controlling. As a teen i was not allowed to go to the movies with any friends,go over to any friends house,I was not allowed to have anyone over to my house,and i was not allowed to go to the mall with my friends. I most certainly was not allowed to date even when i was 18. When i started college i communted. Those were the worst parts of college. I was STILL not allowed to go anywhere and do anything. My college was holding a pool party and she said i couldn't go because the lord revealed that there was danger. She once found my vibrator and threw it out saying that masturbation was a sin. She went on to say she found it because the Lord revealed to her that i was sticking foriegn objects in me (feel free to laugh everyone else does when they hear this). Finally sophmore yr I was allowed to attend a halloween party because she wanted me to see partying was not fun. I came back from the party and told her i had a good time and this just sent her on a rampage. She screamed about how if i wanted to "party" i needed to live on campus. So I moved on campus and met a guy and we got engaged. She started to accuse me and him of having and said "if you are having sex with each other you need to stop it RIGHT NOW!" I was 24 yrs old at the time. We weren't having sex but it most certainly wasn't any of her business. Senior year of college she found out i smoked cigarretts because i she saw a ciggarett in my trash can in my room at home. She calls my college apt at 6 in the morning screaming at me about smoking ciggaretts and "forbid" me to smoke again. I still don't know how to drive on the interstate because she refused to teach me how.I was never a troublesome child,I stayed out of trouble,I dont drink and the worse thing i ever did was smoke a ciggarett(ohhhh im a bad *** lol) and I am now 26 yrs old in the process of moving out to get away from her but I am still curious what the hell makes someone so controlling and paranoid?