Having a hard time believing it’s real

I weighed in 12lbs down from my highest weight (Late December) this morning. I just can’t seem to accept that it’s real, that I’ve finally figured out how to make this work. I’ve never managed to lose more than 8lbs, except when I did the keto diet in college and dropped 20lbs (which I immediately gained back and more when the pandemic hit.) In my head it’s just a 12lb fluctuation from my real weight of 275 and I’m fooling myself by believing I’ve lost anything at all. Logically I know I’m putting in the necessary work. I’ve been eating in a consistent deficit for 4 weeks (portion controlling but not counting calories for a few weeks before that), going to the gym 3 times a week, increasing my steps. But I’m not miserable, I’m enjoying how I’m eating, I feel good. I just…..can’t believe it. Has anyone else experienced this feeling of disbelief at results? I’m so scared it’s all going to disappear suddenly. Why is this time so different from the others?