I too started working out (crossfit) about 4 months, and just about a month ago I started to feel a lack of nutrition as well. The trick for me was to drink 1-2 litres of water, eat more protein (especially after working out), and eating a number of small snacks when I was hungry rather than meals.
As for what I eat, after a workout I will have a 2 scoop whey protein shake, blended with a banana and a dollop of orange juice concentrate. Followed by my lunch and an afternoon snack of pineapple and cottage cheese.
An hour or more before I snack on edamame, crackers and a protein bar.
In my water bottle I have my own blend of (1 scoup) Poweraide, matcha ( 1 tsp) and water (750ml), which works well for restoring electrolytes and giving me an long lasting energy boost for the workout.
I am still working on the balance, but this is what is working for me so far. I hope this helps.
Everything Michael suggested looks great and it will help you although I wouldn't use soy myself but that's just my personal taste.
Download myfitnesspal on your phone and track everything! You want to grow so you need a lot of calories coming from high protein diet. There shouldn't be one day when you are under the calorie limit .
App is very simple and you will love it.
Good luck with bulking up!