I think I have OCD ? What do I do?

It started in middle school , I did weird things like turn my door knob multiple times & I would have to count in my head to a multiple number , I would step in certain areas in the floor & if I didn't it wouldn't feel right . Or I would think something bad will happen . I have to point my feet in a cross direction everytime I go to sleep . I have to straighten certain things or it will get to me . I have yo make sure all closets re open if I see one open . I noticed this true lie show on MTV about OCD on my freshman yr on hs and I couldn't believe it. How they felt the same way . I thought I was the only one . I never knew about OCD meant . Now I'm about to be a junior .. & I'm wondering if I should get help today I was watching a movie && I kept outlining people figures on tv & I couldn't stop till I got it right . I got so frustrated && I felt so anxious . Everytime I try to stop I close my hands & squeeze them tight hoping it won't get to me if I stop . My sister tells my mon I have OCD but my mom doesn't really understand what it is . So she doesn't ask & my sister makes a joke about it everytime she sees me making a weird step on the floor . She laughed about it ever since I told her I think I had it . but sometimes she gets mad cause she thinks I'm doing it on purpose but I'm not !!!!