Thanks for the concern everyone. We took him to the ER but his bladder was empty so they were unable to get a urine sample, so they sent him home with some antibiotics. In the morning he was dropped off at his normal vet but while he was there they were also unable to get a sample. So Lina (Alexa's little sister) picked him up. However I think she was confused by the crystals that they sent her home with so she wasn't able to get a sample. So it looks like he'll be going to the vets again tomorrow.

The good news is that Tuna is acting totally normal, he doesn't seem to have any problems peeing. He's still as loving as ever and he still is eating like a little pig. I hope that it was just an infection and the antibiotics have cleared it up. But we still want to have a urine sample taken just to be on the safe side.