Missing Calendar Events on iPhone

My iphone said the storage was full this morning and was acting rather wonky - certain apps wouldn't load, screen was freezing ... so I deleted some text conversations, photos and videos - that is ALL that I deleted. However, now all of my manually entered calendar events are gone! Everything from the past and future, GONE. These events contained incredibly important information such as dates friends died, doctors appointments, travel dates, things I promised to do for people ... etc - I rebooted my phone like 6 times ... did a calendar restore from iCloud ... updated to latest IOS ... nothing worked. How do I get them back!? Help!