YOU fight for your raise
Whether the provided raise is deemed "not enough" or you simply assess you're worth more to your employer it's squarely on YOU to fight for your raise. That means if they offer a 3% raise and you want 5% it's up to you to fight for that raise. Traditionally this is done contacting your boss.
What are you worth to them
Keep in mind what your paid has nothing to do with your intelligence, skill, abilities, experience, etc. In a healthy working situation what you are paid should reflect what value you have to the company.
Essentially the company has to benefit sufficiently to offset what they pay you. Even if you are the single most talented human being to ever walk the face of the earth, if you're only making me enough to reasonably pay you 35K a year... you get paid 35K a year. (Of coarse arguably that means I'm utilizing you as a resource poorly, but that's another issue)
What to do now
First, you should try and figure out what you think you are reasonably worth to your company. Often new people to the working world go "the average person in my role here get's paid X I get paid Y, Y is less than X therefore I'm under paid" that's not always true.
Then you need to fight for what you feel you are worth to the company, If you are worth more else where, perhaps you should pursue other options. (Note, if you go into fight for more you should also start looking for other opportunities. Often you have no real teeth in your argument unless not giving you what you want means losing you)
Supporting story
I've worked jobs where I was helping people in education. I busted my butt and really made a difference in my community, but this really only made my employer a very small sum even taking in consideration grants, as such they could only offer me a small sum, well under what was "average" even for the lowest of entry level in my area. (There were a number of benefits that helped mitigate it, but even then for my skill level I was really low on the totem pole)
Simple fact was, I was only worth a small amount to my employer, even though they loved my work, and I was really making a difference in my community. Sadly the only way to really get what I was worth in skill and talent was to find a company who could better utilize my abilities asking my previous employer for what I was "worth" would have been both unreasonable, and unrealistic.
(Imagine you're hiring a world famous painter to paint your deck white, no art, just a single solid color of normal latex paint... Is that paint job worth a few hundred dollars because that's it's value, or millions of dollars because who did it?)