Next, go to the search bar and type in that person’s username. If it comes up, but you’re no longer following the account, then you’ve only been removed as a follower and not blocked. You can request to follow the account again — though before you do, you should consider why the person may not want you to follow them if they went through the trouble of removing you.
If the account doesn’t come up, then it’s possible you were blocked or the account was deleted.
Source: https://www.distractify.com/p/how-to-know-if-someone-blocked-you-instagram