I'm sorry about your grandma, Sometimes in those situations the best thing is before you drive yourself crazy with stress and anger, the best thing is to remove yourself from the item/ person that is angering you. Try going for a walk, that always clears my mind
or going to a store you like and getting your mind off the subject. We have a reptile store up here that I like to hang out at, just to cheer myself up. Try going somewhere you like, that way when you get home you will have a fresh mind and maybe the person that was stressing you out would forget all about everything
Another thing that helps is hobbies, I myself like art, it's a good way to express yourself, or you could try music, just a way to clear your mind, I hope this helps a little, and no worries things will get better
I know how you feel, my dad was always the same with reptiles, that's why I had to wait till I was on my own. I had a African Clawed frog for 17 years when I was younger, He would always tell me " Go let it go in the brook" -_-