Please help me. I’m really scared about this and I don’t know what to do. I’ve never gotten this kind of email and I was stupid and replied.
The details about (alleged) sender of this mail are missing so one can only speculate from your behavior that this mail is completely unexpected for you. In this case it is very likely a typical phishing mail where the sender tries to lure you into clicking on the provided link and then enter your credentials to some service (Mail, Netflix, Paypal, Facebook ... - targets vary) so that the attacker can misuse these credentials.
If you did not click on the link and filled in the form but just replied to this mail usually nothing bad will happen. The worst thing is that the attacker will see that the mail account is actually active and that you will get more such mails in the future or that the attacker will try to lure you with more targeted mails into providing credentials, executing malware or whatever. Just ignore these attempts.