Is my behavior normal, helpful or counterproductive?

It is completely normal to grieve for the loss of a loved one. Do not listen to anybody that tells you otherwise. It is fine to honor her life with pictures, and is perfectly alright to cry. You can still be around animals and make a HUGE difference without taking on the financial responsibilities of a pet. Try going to your local shelter and play, help feed, pick up waste, etc. I think it would help you immensely.