I take about 1 to 1.25 lbs of food per day for a 5 day trip with an average of 6ish miles per day. Granted, 6 miles a day is about what we are
supposed to walk every day... but there is a big difference between walking with a backpack 6 miles, on a trail with 2000 ft of elevation gain and loss and walking 5-6 miles around my house.
On a 5 day trip, I'm just not that hungry. I'm less hungry on a 5 day trip than I am even at home. Sometimes I have to actually force myself to eat, a little.
I also take about 2200 calories per day. Dehydrated meals often have a VERY low calorie count. You might want to add up the calories, in addition to the ounces. You might feel kind of crappy on day 3 if you are only eating 900 calories a day.
It also makes a difference if you are doing 6 mile days or 20 mile days. I can't do 20 mile days, any more. But even when I was doing 15-20 mile days... I still wasn't that hungry on a short trip.
I (sadly) lose almost zero weight after 6 days/5 nights, if I have 4 slices of pizza when I get home. A word of warning: Don't eat like a thru hiker in town for 2 weeks when you get home. It is really easy to tell yourself that you burned a TON of calories backpacking for 5 day and to eat anything that isn't nailed down and gain weight.
I'm 58 years old, 5'2" tall, and weigh 138, and female. Your mileage may vary. But it is very common for people to be less hungry on a shorter trip. It is also VERY common for people to overestimate how hungry they will be and to take too much food. But it looks like you might be erring on the side of too little food/calories... maybe... maybe not.
My goal is to end a trip with one mustard packet.