This will prevent progress whether you’re shooting for 2,800 calories or 4,000. To put on 45 pounds, you need to eat enough calories 7 days a week, for the next 52 weeks.
Right now, you’re varying as much as 25% per day. Some people use that tactic when they’re cutting weight. I suggest you simply focus on eating no less than 2,500 calories for the next 14 days and watch what happens.
What, exactly, did you eat yesterday?
Going forward, you can either try eating a few big meals or a bunch of smaller ones, whichever suits your appetite and schedule the best. In the big picture, the results are essentially the same. 3 squares of “big breakfast, big lunch, big dinner” put plenty of size on plenty of guys for about a century.
You’re gonna want to check @robstein’s training log. He’s a natural competitor (not an assisted IFBB pro), who’s 5’4", competes around 140, and is currently a lean 160-ish in the offseason. I could be wrong, but I believe he’s said his average intake is around 2,200 calories while lifting 5 days a week.