I feel for you having dealt unknowingly with a breeder who is not the best. Good that you are taking him to the vet ASAP. I agree with others here that without a good health contract to cover possible health issues, it would be very wise to get insurance. It was suggested that you get insurance before the first vet visit. But I think that if the dog gets sick, the insurance company requests a vet history before they cover anything. As you have to get the exam in 48 hours, any health issues will be on record anyway. Praying he is healthy and many of your fears will be allayed.
There is much info on the internet re insurance and it is quite a task to make apples to apples comparisons. One has to carefully consider the coverage, conditions and small print! I did much research and decided on Trupanion and have been very happy with the coverage and service. I have zero deductible and they pay 90% of covered costs. The only issue with Trupanion is that the deductible is for each illness rather than per year. As I have 0 deductible I don't care. They also do not increase premiums with age. Any increases are only for relative vet costs in a given area. I have only had one increase in five years. The other good insurer I have heard is Healthy Paws. The coverage is similar to Trupanion but they only charge the deductible per year.
. But they do increase premiums with age I hear. These insurers are for accidents or illness and do not cover vet visits or routine things like flea meds etc., but there are some companies that do cover such things.
Good luck at the vet and hope your baby is healthy and that you will enjoy her for a very long time.