Frustrated with my lack of progress, feeling dumb

I’ve been working out with Fitness Blender for about a year and a half now, and I’ve gone from being a very sedentary person who occasionally went for a walk or a bike ride to a person who does a 45 minute level 4 FB workout 4 or 5 times a week, walks 14-18,000 steps per day most days, goes hiking regularly, does her own landscaping, etc. I went from not giving much attention to my diet at all and eating a lot of junk to counting my calories, cutting out processed foods and reducing my alcohol consumption. I’ve seen a ton of fitness gains, I have been steadily increasing my lifts and I have more endurance by far, and my resting HR is way down. But during the first 6 months of my fitness journey, I somehow managed to *gain* 11 lbs, and in the year that’s followed I’ve only lost 5 lbs despite all my efforts.

Multiple different TDEE calculators, as well as my Fitbit Alta HR and My Fitness Pal were giving me a daily calorie burn of 3000 or more, and MFP told me to keep my calories at 2150 per day to lose 1.5lbs per week. I’ve been keeping mine at 1800 for the most part just to be safe, with an occasional 2200 day when I do HIIT, weight training and hiking in one day. But my weight loss hasn’t been anywhere near that.

I posted my frustrations on a different fitness forum and got a lot of people saying “well DUH you big dummy, how could you even think that you could eat that many calories? All your trackers are overestimating your activity and calorie burn by more than 1000 calories per day and you need to cut your calories by a lot, obviously.”

Which, I mean, fine. Ok. I just really didn’t think I was eating unreasonably for how much activity I was getting and how tall I am. I get at least 10-12 hours of moderately intense exercise every week, when I used to get almost none. I just don’t understand how I’ve overhauled literally everything and I’m barely hanging onto 6 lbs heavier than I started?

Anyway, I’m feeling terribly discouraged and dumb and unhappy about all of this.