Do you think my puppy is sick, with these symptoms? Please help!?

The first concern I have is that he has a partial blockage or something ingested that shouldn't have been...which may be causing some mild to severe discomfort to him making him loose his appetite. I would have an x-ray done. This could also be the onset of a disease and by catching it early could be the difference between life or death to your dog. Lastly, if your dog did ingest some medication and you wait to take him in, it may be to late. There are things they can do to help stop the medication from doing more damage to him but they need to be done ASAP. Best of luck to you both!