Ok so I'm probably going to attend classes this semester at a Jr. College and I have a job that usually gives me 30 hours a week. Also I study music and play drums everyday so its hard for me to get to the gym as much as I used to.
Wondering since I only go about 2-3 times a week. (lately only two). How bad is it not to being working out my lower body? Will I significantly have a harder time gaining mass if im focused on just my upper body?
My diet is fairly stable and I'm basically not gaining that much but not losing that much with the way it is right now. Is there anything anyone could suggest?

do a full body workout 2 times a week. That would by far be the best option. You will work all muscles 2 times a week so you don't have to neglect your lower body.

Also, lower body lifts like squats and deadlifts put mass on the entire body due to the heavy stress they put the entire body under. When the body is put through this kind of stress it releases hormones, growth hormones that makes your muscles grow bigger.

I could not have said it better myself.

Yeah, it's tempting when you're young to concentrate on upper body. But don't neglect things like squats and deadlifts. In my opinion, YES, you will definitely have a harder time gaining quality mass if you neglect lower body lifts.

I wish I still worked 30 hours a week. Now I am working 40-50. FBW 2x per week.

Best solution would be to go three days,

Day 1 Shoulders and legs
Day 2 Chest and Back
Day 3 Bi and Tri

It also depends on how many days rest you get. For example if you did full body mon and thurs this would be ideal, if not than I would suggest a split

Day 1 Chest Back Bi
Day 2 Legs Shoulder Tri

You can use a tri set system or a superset system with this routine.

No one likes spam.

And that split is crap.

So the first is the best solution but the fbw is ideal? Im confused to which one you're recommending.