I think your graphics card might be overheating, at least I've seen glitches like that from an overheating card. I can see the cross hotbar, but if you're on a PC you should be able to view the temperatures of your card (either with software that came with the card or free monitoring software). If you're on a console might just have to check for dust, make sure it has decent airflow/cool environment etc.

Sorry not a lot of help, but hopefully it's a starting point anyway.