Items disappear when joining world

Hey, this issue all started a couple days ago I was playing on my friends Minecraft server and I got some pretty good things like iron sword, pickaxe, etc.
then the next time joined in my stuff wasn’t there and my spawn wasn’t set when last time i played in the server I did
I had to join and rejoin multiple times to get my items back and where I was left off at
Next time I joined and lost my items I just played like normal and got food and what not then I had rejoined again and I had the items I first had and also new items I had when my stuff was all missing
Not sure what’s happening or how to fix this