My Dachshund has lost appetite

My Dachshund has lost his appetite and started sleeping all the time. He is 8 months old. He is also making a sound like breathing difficulty when rolling over pls help

Hello - there are some flags here.  It would be very unusual for such a young dog to be sleeping all the time and off their food, unless they were ill.  It also sounds as though he may be struggling to breathe or in pain.   These all sound like good reasons to ask to be triaged for an emergency appointment by your vet;  they could ask more questions and establish how urgently your boy needs to be seen, so it sounds as though it might be well worth giving them a call.