We just moved last month, so I constantly have a list of things going on in my head of what needs to be done around the house. If I can not concentrate on actually getting my studying done, I go into the garage, see all the boxes and decide that I will go study. Serious.
Anyway, maybe it would help if you plan ahead that you will study for 30 minutes, then take a 20 minute break. Set a timer and just work for that thirty minutes, then get up to do something for your break and then get back to it. This way, when you think "hey I should go do ________" you can just remind yourself that you can do it when the timer goes off.