Is my diet ok for building strength?

I am a GAA player currently following a gym program. The program is focused on upper and lower body strength and explosiveness. I am a bit flabby in the stomach but my main aim is to build muscle. I am 6'2 and 22. I weigh 13.5 stone

My current diet is

Breakfast
Bowl of Porridge

Mid morning snack
one avocado or scrambled egges (2 eggs)
Cup of green tea

Lunch
Sandwich on Health Grain Irish Pride Bread
Chicken slice or tuna
mixed lettuce or spinach
light mayo
slice of galtee cheese
one tomato

half a sweet potato
banana
half an avocado or scrambled eggs (which ever I didnt have earlier)
half an Ugli fruit

Mid afternoon snack
Apple
sometimes a banana if I was too full after lunch

Dinner
Dont really have a set dinner usually meat veg and potatoes or something like a chicken curry.

Late evening
I usually have something like 2 biscuits if Im hungry

That would be my typical Mon-Fri my weekends vary a bit more. I usually would eat more pasta and stuff I have more time to cook.

I also would have a protein shake after I go to the gym and after a training session if it was hard. I usually gym/train every second day. I go to the gym after work so I get dinner at 7. If i have training I would have something like two slices of toast at 6 so it would keep me ticking over before I get my dinner around 9.

Can someone give me a bit of advice? It feels like I'm not eating something right or not eating enough. Thanks.