My messages was classified as spam

1) Don't look for a job on Facebook. Use an appropriate channel for that: Upwork, Dice, LinkedIn, Indeed, Glassdoor, and the like. Even Facebook Marketplace no longer allows job postings. The only thing you can do is answer job postings, on individual company pages. Their /jobs page no longer works.
2) Sending a bunch of messages to people who don't know you is the very definition of spam.
3) The people who you were messaging aren't clients. They're barely even cold prospects. If your real clients have no way to reach you other than through Facebook, well, that's on you. Always use a channel you can control. 95% of the time, that's email. The other 5% is a form on your own website. Don't entrust this to social media.
4) "A little overboard" and "so many messages" are contradictory statements. If Facebook is dinging your messages as spam, then you went more than a little bit overboard. Again, this is the textbook definition of spam.
5) Can it be fixed? I am doubtful.

Can you learn from it? I sure hope so.