It sounds like your poor Degu is quite sick. Rodents have a very fast metabolic rate and need to eat often so 3 days of reduced or absent food intake is quite concerning. You described difficulty breathing as one of his symptoms as well as blood coming out of his mouth. This may be associated with an upper respiratory tract disease which are common in rodents.
Treatment includes oral antibiotics and supportive care with some rodents completely recovering and others falling ill again once the antiobiotics finish. Without treatment, most patients have a very poor prognosis suffering unnecessarily as they continue to decline.
I know you said that you live in an area where there are no vets that know how to treat Degu's but are you able to get to a vet that treats rodents such as mice,rats and guinea pigs? Most vets have some experience treating these more common household pets which are very similar to Degu's.
I hope your little friend feels better soon.