Sims 3 Pets on Macbook Air keeps glitching/freezing/graphics won't work

Hey everyone,

I've had some trouble with my Sims 3 Pets that I bought online from ea games onto my 2013 Macbook Air. It's had some problems and I thought it was about time I asked for some help.

1) When I first open Sims on my launchpad to play, 2 or 3 copies of the application open up followed by a pop up that says "Sims 3 Pets unexpectedly closed, would you like to reopen it?" and if I click No, or exit the pop up it runs okay and gets to the main screen of Sims fine and dandy.

2) In Create a Household, the screen always freezes when I go to finalize the household (on the edit relationships screen). I can see the words with no background (or the same background as it last was in create a sim), and sometimes I'm able to click my mouse around the screen until apparently I click some hidden button and proceed to the next screen.

3) If/when I finally make it to move my sim into a house - the same thing happens where there are words but no background or obvious buttons available so it's very hard to read and or even use.

4) If/when I am able to get the sims into a house and get to the Live/Buy/Build screen, many boxes are just rainbow colours and nothing seems to work.

ANY help or guidance would be greatly appreciated.