I have been in the exact position where you have been. I have found this to be true - You need to do everything perfectly and in sync to see gains. Let me elaborate.
1. Inside the gym - No cutting corners. That last set looks impossible? No. Do it. Push and get those reps in. Don't skip exercises, however tired you may feel. Also, keep on increasing weights that you lift at regular time intervals. Every fortnight or so. 2. Consistency - Stick to the schedule. Don't skip gym. Don't go multiple days/weeks without gym. If you have to travel, do calisthenics, or even simple stuff like pushups, crunches.
3. Eat - As many other people on this sub, I also used to find it difficult to eat. There was a time when I used to go to gym but I would eat only two times a day (lunch and dinner, that's it). The result was ripped, low body fat body but low weight and plateaus in the amounts of weight I could lift. 4. Simple math - I used to always come up with BS excuses for myself. Healthy food is expensive, I can't stomach more food, blah blah. It took me years to gain the realisation that putting in weight is simple math and there is no getting around it. You have to eat more calories than your body uses it. Figure out the ideal proportions of amounts to be taken and keep to it. (This sub's FAQ is pretty good.) Now, I have to shit 2-3 times a day but seeing myself gain bulk is rewarding.

Set a routine for yourself such that all these things work together to make you swole!