I'm sorry to hear you are going through a worrying time with your parents' health at the moment. I've also had lots of issues around bleeding/spotting over the past 3 years. I'd never before had the slightest variation in my periods, they were always exactly on time, so I was really worried. I did go to my doctor, and then to a gynecologist, and as the problem was persistent, I ended up having a number of exams, pap tests, and pelvic ultrasounds. With each one, I worried before, during, and after the test, and went around clutching my cell phone and waiting for the dreaded bad news. But all my tests came back normal, and no one was ever able to pinpoint a reason for the bleeding. Even going on the Pill for 6 months didn't help. Eventually, I got pregnant. That stopped it!
At 30 years old, your bleeding is really unlikely to be cancer. Hormonal disturbances and infections are more likely causes.
Even post menopausal bleeding, which is definitely a red flag, is usually not cancer. (Although it is essential to get it checked out.) It can be a sign of fluctuating hormones too, or polyps. My grandmother, who was over 80, was so terrified by her bleeding that she didn't tell anyone at first. She just quietly bought sanitary pads and put up with it for weeks. Eventually she went to the hospital, and was diagnosed with a prolapsed uterus. Apparently the positioning of it was causing irritation and bleeding. She was fitted with a pessary and all was well.
I suspect that if you go to the doctor, they are unlikely to set you off on a "path of tests" because of this one incident. More likely, they'll quickly press on your ovaries to check for tenderness (meaning infection) and then offer some reassurance.