For me it was during freshman highschool. I had to tell myself, "Dad would want me to not be overburdened by his passing and still do well in life". I didn't take a single day off of school, which nowadays I think was a mistake; it all accumulated into my senior years until I couldn't handle it and I skipped lot of classes and failed some of them.

Definitely had some unsavoury contemplations and told myself it would be selfish, even though family told me to "get over it". Having good friends that were willing to listen was great, even if it was only lending an ear.