Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
How long has he been showing signs?
Any retching, gagging, lip licking, drooling, or vomiting?
When did he last pass urine? Feces? Did you mean he is straining to go?
Are his gums nice and pink (not white/pale)? Moist or sticky?
If you press on his belly, does he have any tensing, tenderness, discomfort, or pain?
Could he have eaten anything he should not have (ie bones, toys, plants, chemicals, human meds, etc)?