Hi mate,
It doesn't look from your diet as though you are eating enough. My rough guess is that your are only eating about 1600Kcals, with perhaps 120g of Protein in there.
If you want to back on some lean muscle you'll need to eat a fair bit more than than IMHO.
I'd say eating to closer to 2500kcals would stand you well. Eating more could be beneficial - say maybe 3000kcals.
Try and get over 200grams of protein down your neck per day, along with some quality clean carbs.
Chicken breast is great if you can get it down your neck
You're having oats for breakfast, why not try getting some oats from somewhere like MyProtein which you can mix with milk and whey to make a nice breakfast shake?
Hope this helps mate.