I think i have OCD/paranoia?

when i was younger, i was afraid of germs and eating out. at restuarants i'd make my parents taste my soda first and if i was eating fries or a burger i wouldnt eat the part my hands touched. i have since gotten over that. but now on my tv, i never put it on an odd number especially 13. i avoid cracks in tile/sidewalks etc and play games with my mind like "if you do this then this won't happen" i'm constantly worrying to the point where i've been worrying about the same thing for 3 months now yet this thing happened nearly a year ago. i'm always worrying and expecting the worst and convince myself something bad will happen if i don't think about my past mistakes. i like things lined up neatly on my desk and get bothered if they aren't. im always fearing something bad will happen to my family and literally convince myself the worst is going to happen. please help, i want to tell my mom but i'm afraid because last time i did she didn't take me seriously. i honestly cannot keep going on worrying about stuff anymore and letting it get in the way of my daily life but i feel like i'll never ever get better. what should i do