Unplug the internet!!
If it's mid-term week, you should be studying instead of being online and making social arrangements with Greek and/or non-Greek friends.
Invite your non-Greek friends to study with you this week and chat about some future plans.
The sorority will still be there, with plenty of social plans, when mid-terms are over. You don't have to go to everything, so don't stress.
Good luck on your tests!
ETA: I sounded harsh when I originally posted, and that's not at all how I meant it!