I have been trying to clean up my diet but I am struggling with staying satiated. Any thoughts on how my food intake for today looks? I have been so all over the place with my eating (and I tend towards overeating) that I am not even sure what normal should look like.

I woke up at 7:15 and since then I have eaten (mostly grazed all morning):
1 glass of smoothie that had watermelon, strawberries, spinach and greek yogurt (around 1/3 of a cup)
1 rhubarb crumble bar (2x2 square)
1 slice whole wheat toast with 1/2 an avocado
1 cup watermelon
Mug of tea

After all of that I was starving at noon and just ate tuna salad made with yogurt (1/2 can of tuna) with 1/2 an avocado and a glass of water.

I feel like all I have done so far today is eat! I was hoping that the fat from the avocado and the greek yogurt would have helped but it didn't work.

I would appreciate any suggestions, I really want to stop eating junk. Because my work schedule fluctuates so much during the week I eat at different times every day and I am often caught off guard by how hungry I am and then wind up eating something awful.