How to not have anxiety about what people think about you.

You are suffering from a severe case of egocentricity.
How many times do you think about other people in a critical manner ?....probably very few !
Everybody tends to be primarily interested in 'self' and not 'others'. Those people you imagine are thinking about you give as little attention to you as you do to them.
Once you understand that, you can throw away your medication.

Medication is not enough. There must be counseling to go along with your efforts to release this anxiety.

Are you in counseling? Who prescribed the meds? That says at some point you had some kind of counseling.

It can help to develop a more independent sense of ethics and moral judgment. If you have ethical/moral clarity for yourself, and you adhere to a personal set of morals/ethics that you consider adequately respectable, you can defend your choices to others. Then, if you have to deal with people who are critical of your moral/ethical choices, you can decide whether you in fact value their opinion, or whether you think it is based on moral/ethical reasoning that is flawed in some way.

To give a simple example, let's say you have a more forgiving aesthetic standard for clothing than someone else. Let's say you think clothing is acceptable if it is sufficiently modest and clean, but someone else thinks it has to be fashionable, have certain brand/status, etc. Now you have the ethic that modest/clean clothing is good and people who judge some modest/clean clothing as inadequate for other reasons are hypercritical. At that point, you can dismiss their social judgment as being 'nitpicky' or 'oversensitive' to issues that don't really matter. You can encourage them to get over themselves and respect others for having clean clothes that are sufficiently modest. If they fail to respect your morality/ethics, that's their problem and you don't have to worry about pleasing them.