I have played Minecraft for years now and never had any issues like this, other than some lag. It has worked fine in vanilla form. Then I installed mods and it still worked fine for around a year. I stopped playing for a few months and when I logged back on I found the new 1.13 edition! I played it in a separate, new world. Then I got this bug where if I walk around a little and hold shift (My run key), I get stuck and keep walking forever unless I close the game. I use task manager to close it but when I do I see a purple screen behind task manager. Idk if this is useful to you. I quit trying to fix it and the next day I logged on and I don't have to hold run and I still bug out. I am 99% sure it isn't a hardware issue, my laptop works fine with any other game or program and this game worked only a little bit ago. I dont know how to fix this, please help. I hope this is enough info, Im sorry this is such a long report. I played on 1.13 and 1.12/1.12.1