blocks not disappearing or appearing

When I break blocks or place them, they aren’t doing as they are supposed to. It shows them breaking but they just become invisible, causing my character to get teleported around instead of walking through that path. If they are placed, it will show them there but when I go to jump on them, they don’t work and I just fall through. I can’t play like this as it will cause my character to die from falls or in lava, etc.