I think someone is trying to hack me, what can I do?

Generally, you should use strong passwords and two-factor authentication.

Instagram, being owned by facebook, uses your Facebook password by default. I’m guessing that someone has your Facebook password and is trying to log into Instagram using the same password. The text message you’re getting sounds like a two factor authentication check from Instagram. This is may be because you have enabled it on facebook or possibly Instagram do automatically it for new accounts. You need both the password and 6 digit code to log in. Without it they shouldn’t be able to access your Instagram account or make an account and pretend to be you.

I can’t remember if Facebook signs you out on all devices after a password change but it might be worth doing that just in case it doesn’t.

If you use the same password for your email account as Facebook you need to change that as well plus every password for everything else just to be on the safe side.

If you haven’t already would recommend you activate 2 factor authentication (2FA) for any account that offers it. to add an extra layer of security.

Someone may be trying to get you to click on the links being sent to your phone or they may be trying open an Instagram account under your facebook name. Change that facebook login ASAP. This is probably not a virus but if you’re not using an antivirus program and safe web browser I’d do that ASAP as well. Then a VPN. Be wary of any links sent to your phone through messaging apps in the next few weeks.