My 8/9 year old golden retriever has been acting a bit strange lately. She hasn't been eating her food when we give it to her, only a couple hours after. She has a very dry nose. I guess she's been very "lazy" lately, lying around and not responding to anything that usually excites her. I also noticed a tiny lump on her side, that you can kinda move around. She has a strange scar on her "elbow" that she's had since I could remember. Sometimes she goes back to her normal playful self and has a wet nose, but usually not. I don't know if it's normal that her head is warm whenever I pet it, or if it's just the summer heat. Please help if you can, I'm really worried.