Newbie here. Long time lurker, first time posting

Here's my situation, all insights welcome!

I would like to lose maybe 10 vanity pounds. I eat fairly primal/paleo. I do eat some dairy (mostly cheese)-it doesn't give me any digestive issues and it is an easy, portable snack. My issue is I can't seem to lose any weight or really reduce body size during the week, only on weekends. It is weird and makes no sense.

I work in a hospital and have to eat in the cafeteria each day. For breakfast I usually have scrambled eggs with veggies. Lunch, every single freaking day, is a spinach salad with grilled chicken breast, hard boiled egg, olive oil dressing. Dinner is whatever protein I can find at my house. I usually eat a little fruit or peanut butter on days I work out. On the weekends I usually eat more protein, fewer vegetables.

So for some reason, I usually can lose a few lbs over the weekend. They then immediately pop back on when I eat a salad. WTF? Now, I completely understand that small fluctuations like that can be any number of things: fluid retention, etc. If it wasn't so long term, it wouldn't bother me. I also know I shouldn't get hung up on what the scale says. But I just don't understand why nothing seems to be happening over months worth of fairly clean eating. I definitely fell off the wagon around Christmas. Prior to that I had been somewhat successful with my patented "only losing wt on weekends" approach. Two steps forward, one step back. But at that time my wt was actually trending downwards, so I could ignore the day to day fluctuations.

It makes zero sense to me. What the hell is happening in my body during the week?? I know I'm not eating that many carbs during the weekdays. I know I'm eating enough calories and not too many. I know I should let go of the scale, but I swear my pants aren't getting any bigger!

Any ideas??