Where the F are the KEYS!?

I play consistently 4 hours a day on weekdays and 6-8 hours sat-sun for the past month. I only play night raids with the occasional regular mode thrown in. I have not acquired a single key in the last couple weeks. Is this normal??? I open EVERY. SINGLE. BOX. I come across. I had duplicates of a lot of keys and now nothing. What the hell is going on!!