Hi! Don't worry, is normal. I donated to my husband almost 3 months ago and at the beginning my stomach also hurt for some time. The place where your kidney was will be filled with "other things" that are inside you...You will be ok, try to walk...it will help you. 2 weeks is so little time....
Now, after 3 months i also have low back pains, but we just have to give ourselves more time. They told me that you are completly recovered 6 months after surgery.
Sorry for my english, i am from Madrid, Spain.
I wish you all the best!!