I'm worried because my appetite has become so intense that my stomach doesn't feel good.

A few months ago, I went to a buffet and ate way too much, which made my stomach feel uncomfortable and difficult for several days. Recently, my appetite has increased, and I'm worried. I used to eat well and enjoy my meals, but I didn't eat to the point of stomach discomfort like this time. My blood sugar was slightly high, but lately I suddenly feel very hungry, eat very quickly, and consume more than usual, always feeling overly full. Yesterday, I left some meat because I felt bad about wasting it, but I couldn't digest it and sat until 1 a.m., eventually taking medicine to help digestion, vomiting about three times, and finally falling asleep exhausted. Today, my stomach has been upset all day, and I have a headache. I couldn't even prepare meals for my family. I just made a simple dinner with what was in the fridge, including tofu and kimchi in a stew. It feels like my appetite suddenly increased, and I wonder if it's related to the three classic symptoms of diabetes: polyphagia, polydipsia, and polyuria. Could my high blood sugar be the cause? Also, even if it's not a health checkup, can I get a fasting blood sugar test at a general clinic? I think I should get tested once. Should I buy a blood glucose meter and test myself? Or should I go to the hospital for testing?