Hello David,
I would start off by scanning your computer with anti-virus and anti-malware software.
Second I would step up my password game by using 12-15 characters and avoiding real words, so changing all of your passwords is a good idea as well.
Enabling two-factor authentication on any service accounts that offer the feature.
Practice smart habits moving forward, only visit sites that have HTTPS at the beginning of the URL, possibly setting up a junk or garbage email account that can be used for unimportant profiles. So many sites require a sign-up process these days, and having them tied to your main email account isn’t ideal.
Lastly, taking a close look at your financial accounts, make sure no money is missing, and look for any suspicious transactions.
I hope that helps!