Dog Started Peeing in the House?

My husband and I rescued Buffy from the pound about 3 yrs ago. She is the most well potty trained, politest, and sweetest dog we've ever owned in our life. When we adopted her we lived in a house, but in February of 2014 we had to move into an apt. She adjusted just fine. We go on walks more and play more. She always lets me know when she's ready to go outside for the bathroom. But last night I let her sleep in my hospital bed with my heated blanket like normal, but I awakened somehow to see that she had peed in my bed. Yes I was angry, but didn't scold her. I did send her out on our couch for the rest of the night so I could wash my bed linen. I also took her out for more potty time. My bed linens were done and so I made my bed and told her to sleep on the couch only to get up to find she urinated on the couch, at both ends of the couch. I noticed her special spot is poking out and seems to be leaking a little. So I don't know whether to be concerned or start get frustrated with her. What should I do, take her to the vet or just buy baby diapers or is there a more serious health issue I should be concerned with?

By Christy F.