Good news and bad news about Goya

First the good news.
Sometimes Goya surprises us. When we got home from work three times this past week, Goya was not in the room where we left him. We don't know if he managed to get into a standing position and walked, or whether he crawled (well, once he was on the back landing -- 5 steps down, so I hope he walked). He never does this when we are home. When we are watching him, he only gets into standing position on the sidewalk in front of Starbucks. He claims the other surfaces (grass, carpet, tile) are too slippery for him to get up.

Now the bad news.
He is limping on his left front leg now occasionally. It does not seem to be associated with the days he surprises us. Sometimes it is in the morning, sometimes at night. It has been getting worse since Sunday. Sunday morning he limped a little, we gave him some aspirin and he seemed to feel better, so Gary walked him to Starbucks. Monday it seemed worse and he didn't want to walk all the way to Starbucks. He just walked to the corner, got distracted by meeting another dog, and wanted then wanted to walk home again. This morning, he was limping so badly that we didn't even try to take him to Starbucks. We are trying to get an appointment with the vet because he now seems to be in pain, whereas before he just seemed weak. I'm worried.