1. The dog part could be your problem because scabies can live on dogs for up to 5 days then the scabies mite will either die or look for a human host. So it is possible you keep on getting reinfected by the dog.
2. Washing temperatures are not really important it is important to keep them in the dryer for up to an hour as this will kill any scabies mites in your clothing or bedding.
3. I would use a dryer to ensure your killing the scabies.
4. You do not have to iron just use a dryer.
5. You can leave your mattress and other items in a secluded place for two weeks and they should all be dead.
6. Other stuff around your house seal in sealable bags or containers
7. If you have a severe case of scabies you may need both sulfur and ivermectin. I think shots are for horses for humans they give you pills.
8. For cleaning of the floors use bleach cleaners so they kill any scabies lingering
9.You can get a pocket microscope for 15$ buy
pocket microscope here10. You certainly need to treat your scalp or they are likely being forced to that area. Put it on your face as well as sulfur is safe.
It is possible as scabies is known as the 7 year itch. What I think is say you had it for a year before you started treatment, it will likely take a year to treat and possible a year for the post scabies conditions to go away.
Hope this helps!