Lost all of my calendar except birthdays

As I was going to bed about a week ago, I plugged in my phone to charge as I do every night. It asked my for my apple password, which was weird, but I put it in and went to bed. Woke up and all my calendar events were gone (except for birthdays). All of my contact information was also deleted. I turned it off and back on and all my contact information was restored (except for my boyfriend's info) but all my calendar appointments are still gone. I logged into icloud and my boyfriend and the calendar appointments are gone from there as well. Any way to recover the calendar? All past and future events are gone.