New Plane - Entry into Control Zone Denied

Join me in welcoming C-GUVH, my "new" Cessna 150M!
It was a beautiful day which means it was a busy day. The Oshawa practice area was filled with aircraft and CYOO was experiencing a very high traffic load. The controllers there were doing an excellent job, but were unable to take on more traffic. I held for a bit north of Port Perry, but decided to divert back to my current home base of Edenvale (CNV8).