Inventory Reset

So I went to freebuild to see if I could get a plot. I realized I like survival more, so I went back to it and my inventory was reset to its state that it was in like 10 days ago. I therefore lost:
2 newly purchased Cow Spawn Eggs
Full set of Diamond Armor (the chestplate was enchanted to Protection III)
Old Reliable (diamond axe with Efficiency V, Silk Touch, and Unbreaking III)
A neat Diamond Pick that Wairoa just gave to me as compensation for a banned user who had my pick (with enchantments something like the axe???)
And worst of all, a stack of Baked Potatoes.

@andy_ @_specialk @Kyle8910 @Johnlh97

Just happened again. me and Callum were building a castle and he lended me a pick and a shovel (diamond). They both had Unbreaking III and Efficiency IV, and I went to creative, come back to survival, and I suddenly have lost the tools and my inv was reset to the same the last time it happened.