I am having voices in my head and I keep seeing shadows should I tell my therapist?

For context I am under 18 and in the uk and after experncing ptsd that I have diagnosed with I seemed to have developed hallucinations I have also notice I may have some delusions of thinking I have done something terrible and the worst person alive. The problem is I don't really want my perents to know because they are having a stressful time at the moment and they have said to me before "thank god you don't have hallucinations as I wouldn't know how to deal with them". I keep thinking about this statement and I don't want to harm them because they are nice people so idk what to do. Plz give me suggestions on what to do.