First off, I dont think your crazy to take the baby if the Mom stopped feeding. It is better for them to stay with their littermates until they are 8 weeks because they learn pack order and all kinds of things WE cant teach them. But, If I were you Id take him to the vet and make sure he is ok and ask if there was anything he would suggest I supplement him with. Also, I wouldnt take him anywhere before I got his shots. These little ones are very sensative and can get sick easy. I would also suggest a heating pad on a low setting or hot water bottles at night if you use the A/C already. Dont want him getting too cold. Other than that, just love him like theres no tomorrow. ( they are just like newborn skin kids, lots of time, patience and love)