The villagers all disappeared by day 3

So, everything was fine for the first few days. I set up camp, so to speak, in a nearby village. I took up residence in one of the houses which appeared (for three consecutive days) to NOT have an owner, so I made it my house. Built a basement and all that nonsense. Really made it mine. On day 3 or 4 of playing this file I logged in with the specific intent to go trade with villagers and was absolutely blown away and devastated to find that ALL of the villagers, EVERY SINGLE ONE, was gone now. No evidence of a fight, no damage to the houses, they all just disappeared and left absolutely nothing behind and they never came back no matter what I did. I even found a new village, in the same exact file, which was even bigger than the first village. I celebrated then almost IMMEDIATELY cried and got all irritated when I learned that the new big village is ENTIRELY DEVOID OF RESIDENTS.  WHERE IN THE WORLD DID THEY ALL GO, LIKE, HONESTLY, I want to trade and really interact with these villagers, and I can’t do any trading now. I’m so disappointed and I have no freaking clue how to fix this but it’s really sincerely ruining my Minecraft experience. This is one of my favorite games but this issue is sincerely reeeaalllyyyyy ruining the experience for me, I can’t have fun with this bugged up version of the game. I have spent way too much time mining diamonds and stuff to just restart another file but even if I did I’m confident the same exact thing would happen and all of the villagers would just straight up disappear one day without any explanation. PLEASE PLEASE help me. Please.  My email is [...] - please email me any time, day or night, this is really important to me.  Also my phone number is +####. You are welcome to call me, if that helps. Thank you. 

Max picatti