You can get over social anxiety on your own, all you need to do is practice socializing whenever you get the opportunity. Even if its scary, challenge yourself. Take small steps and with each step, do something that is more challenging. Each time you practice being in a social situation like 5 times or something, you adjust to that situation and you are ready for more challenging situations. Also, when you are in social situations, you have to learn to be comfortable in them.
Relax your body and muscles, take deep breaths, and tell yourself that you'll be okay and that you are in control, no matter how anxious you feel. Also, act confident. When you do these things, with time and with challeing yourself a lot, you'll eventually overcome SA completely or at least to the point where you have very little anxiety left. Your thoughts affect your feelings, your feelings(happyness, depression, fear, anxiety, etc) affect your behaviours(actions that you do, decisions that you make). When you learn to control your thoughts, you eventually control your feelings/emotions, and from there you can control your actions without feeling much anxiety.
Basically, with social anxiety you want to challenge yourself to face your fears, but one step at a time. Small steps, for example, step outside the house or even go for a short walk. With time, the anxiety from that will decrease a lot. And on the socializing side, try ordering some food or something. Doing this frequently, like once a day(or two but every day helps much, much more) will make you adjust to being in a social situation over time. Once you are adjusted to that social situation, it isnt near as scary as it used to be. Then you are ready to challenge yourself with an even more anxious situation. Keep doing this until you completely adjust to being in social situations.
Also, a big part of overcoming social anxiety is by focusing your attention outwards, not inwards. Instead of thinking about your anxiety so much, try to realise that you are just another person and that there is no spotlight on you. Focusing your attention on the environment rather than on within will help you to feel much less anxious with practice. Also, pretending to be confident and trying to relax in anxious situations will help you to be confident over time. Ignore any thoughts that make you embarassed or anxious, and dont let anxiety/embarassment ruin your life. Good luck