something is wrong with my nether. 😔

in my survival world i’m doing a lot in the nether because it’s easier to travel though there, but as of late i haven’t been able to go in the nether. when i try to go in my main nether portal my game crashes and my dog is now stuck somewhere in the nether and i can’t even go and get him. i don’t know if it’s because of all the portals i have or if it’s something else i just really want to be able to go back to the nether. also my game has been really glitchy since this 1.12 update so. 😐