My Complicated Struggle with Health OCD

I was clinically diagnosed with OCD about three years ago. My biggest obsession is pinworms. I started feeling extremely itchy all the time and some nights, I feel a crawling sensation on my skin at night while I sleep. Over time, I started to feel uncomfortable sitting in certain places, touching the floor, and carrying or touching my own laundry. Additionally, I shower and wash my hands for more than two hours combined each day.

I have tried treating the pinworms myself, twice with one medication and another time with two doses of a different medication prescribed by my doctor after I told them about my fear. I should mention that I live with my parents and my healthcare provider doesn’t perform pinworm tests. My parents are awesome people, but I’m worried that they’re infected too, even though they keep denying they have symptoms, probably just to keep me calm. From what I’ve read, many pinworms patients can be asymptomatic or have very mild symptoms. I still think I have pinworms and they probably reinfected me after my treatments ran their course. Every time I talk about my worm problem, they treat me like I’m insane and object to treating themselves with me. Also, I have many friends at the college I go to and my immediate family has visited other family many times between when I first thought I was infected and now. I feel terrified and guilty since my entire family and all of my closest friends could be infected with parasites because of me, and I have no way to help them without seeming crazy.

Also, I know people make jokes about self-diagnosing this much, but I think I may also have colon cancer. I have felt constantly bloated for months now, and I always feel a fullness in my lower left abdomen. The size of my excrement has been decreasing steadily for a couple of years now, almost as if it’s being stuffed through something and it’s getting really oily-looking. It’s not because I’m dehydrated, I already ruled that out. Also, recently, my abdomen has been gurgling significantly more frequently and louder than usual. Once again, I’ve explained this to my parents and they think I’m insane, and I’m too scared to make a doctor’s appointment since I’m embarrassed that colon cancer is a really big diagnosis and there’s a chance I might be wrong. I also don’t want to wait until something terrible happens because of the cancer and my life will be in immediate jeopardy.

I’m not asking for medical advice, I just need some help deciding what I should do to help with both of these issues.