Every time I join my world after about 15 minutes or so it will automatically kick me out of my game and when I get back on some of my progress has been lost

Whenever I get on my game after a few minutes I will have a lot of progress done. But my game will crash and kick me out of Minecraft altogether, so when I get back on most of my progress that I made is gone. I would like to know if anyone else has this problem or is it just my sucky Internet and if you can fix this when will I be able to get back on Minecraft.