FRUSTRATION & LOW MOTOVATION SETTING IN!

[PC1]

Hi all, I've been training now for around 2 years & even though I put the effort in I'm not seeing any positive gains & I'm beginning to get frustrated which is causing me to lose motivation.
I train 3 times a week around my work shift pattern which consists of chest & bi's. Back, tri's & abs. Shoulders & legs & about 20mins cardio. I have 2 rest days. My diet is fairly good. 8am 3 scrambled eggs for breakfast, 10.30am a piece of fruit & a protein shake, 12pm chicken & rice for lunch. 3pm tin of tuna & protein shake. 6pm pasta or steak with potatoes & veg for tea. 7.30pm gym. 8.30pm/9pm cottage cheese on ryvita, protein shake & a table spoon of peanut butter.
I've tried my hand at the pyramid training routine but I arnt seeing any change. Where or what am I doing wrong? What can i do differently to see results in muscle size & defination? Any suggestions or adice will be a great help! Thanks