High platelets and rbc according to the lab who ran them, but my doctor never mentioned it to me? accidentally found out by looking at my records. platelets range from 389 to 420. with a family history of cancers shouldnt this be a red flag?

All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Talk to the doctor who ordered the tests. Having said that, iron deficiency is common in women of reproductive age and can be associated with high platelet count. You may take oral iron and multivitamins and retest in 6 months.

Your platelets as listed are in the higher normal range for the majority of labs, upper limit being at 450 K. Connecting your genetic propensity to develop specific diseases, in your case cancer, would take clinical context, such as symptoms and/or current screening guidelines. Trusting your healthcare providers would be critical as your anxiety is understandable given your family history.