Upvote:9
If you stay in the Schengen zone for 90 days, the only way you can qualify for an additional 90-day stay is by leaving and remaining outside the zone for 90 days. You can't be in the Schengen zone for more than 90 days in any 180-day period.
This answer discusses the recently-revised rule: https://travel.stackexchange.com/a/21461/19400. Another answer to the same question links to a calculator: https://travel.stackexchange.com/a/27123/19400
However, now that you've been refused entry, you may have bigger problems. What did they stamp in your passport when they refused you?
In theory, if your work requires you to be in the Schengen zone for more than 90 days in a 180-day period, you should have applied for a different kind of visa. You may be able to make such an application now, though I would suspect that your recent overstay will make it more difficult for your application to succeed.