Unable to use the internet

After buying and installing the antivirus I have the impression that I have made the worst choice possible, I can no longer access the internet, basic sites such as google drive, college system, gmail, outlook, facebook, instagram, twitter, I can't even download a 300kb PDF, I don't want an ativirus like that, I pay for a very expensive internet, it's absurd, no page loads, neither the speed test loads, nor does the avira website itself load, this is absurd without size! SOMEONE HELP ME