I am in-between on the extrovert-introvert scale. I have attended conferences by myself. It can be hard work for a shy or introverted person to deal with the 'social' moments. One solution is to ration your effort to be sociable...
For example, I don't feel the need to try hard to be sociable at coffee breaks. Everyone is busy getting coffee, looking at the conference schedule, checking email, etc. It is very normal to not be sociable at coffee breaks, so you can fit in without problem by getting coffee and then finding a comfortable place to sit and just study whatever you want.
I almost always skip the "party" if there is one. There's nothing wrong with that.
In my opinion, you might want to reserve your main effort for lunch. This is a time when people are resting from going to sessions but are relaxed enough to talk and may have just learned something interesting, too. The two issues here are where to sit, and what to talk about. My advice on where to sit is first of all, do NOT sit at empty table by yourself. This will feel uncomfortable, while waiting to see if anyone will sit there. I also avoid taking the last seat at an almost-full table where everybody is talking. They may be busy with their conversations. I look for a table that has a few people but is perhaps 60% empty. I don't sit on the opposite side of the table far away from the people, nor right next to them; I pick a spot that is one or two seats away. As soon as you sit down, shake hands and introduce yourself. Other people will come and fill in the empty seats. It is normal when someone sits down near to you to immediately say hello, and introduce yourself. They will do the same.
Fortunately, at a conference, everybody has in common an interest in the subject. This makes it easier converse, using standard questions to begin: "Have you been to this conference before?" "Did you travel far to get to the conference?" "Have you used React a lot?" "What did you think of the keynote speech?" "What does you company do?" If the conversion moves to a technical discussion, you may find it easier to talk.
If conversation becomes difficult, you can just listen to what the others at the table are talking about.
Also, people are always busy at conferences and running off to take care of tasks or business, so if it is too uncomfortable is OK to finish lunch and leave; you are not trapped!
If there is a dinner speaker, then dinner is easy, since most of the time everyone will be listening. After the speaker, conversation can be about what the speaker said.
Good luck! There are many people who exactly understand this anxiety and are wishing you the best.