How do I do this? I’m starting to feel bad because all I do is study. I strive for A’s and B’s, and never socialize because I feel I never have time!
I’m either in class, or in the library, studying for something. I haven’t hung out with my friends, or barely talked to them, in weeks. Even my girlfriend is getting worried because I’m always stressing about my next exam, quiz, ect.
How do I balance this out? I also am taking 15 credit hours and I work 2-3 days a week.
I’m taking 18 credits with ROTC which is roughly 8 hours a week and still manage to have a social life. Form study groups and go ask your friends to go eat. 15 credits shouldn’t consume your whole time. I currently have all A’s and put in enough study hours. Make a schedule. MAKE time. At least you have friends! All you really need to do now is ask them to hang out every now and then!
You do have to build your social time into your schedule and reframe what you call social time. You are working hard because you have the goal of high grades and not squandering your college education–that’s a good thing. There are many freshman (and more advanced students) who are out there all over America engaging in a totally social college experience and many will be facing the consequences of having to leave their schools because of poor academic performance.
Like DefineGravity said, your social life can be the meals that you plan to eat with friends, hanging out with a friend while you both wait for your laundry to travel through the machines, talking with a friend while you work out at the gym, a TV show break on NetFlix, or whatever. It doesn’t have to be super time consuming and can be tied to the nonstudying activities that you have to do.
You will get it figured out. It is an adjustment period.
Feels like a little time management shall do the trick. If you’ve already manage to study most of your time I think by now you’d be able to cringe that time. allot a specific time frame for studying so you’d be able to give you friends a shot of having you around again. 
best of luck on the management of time