HELP! DESPERATE! Please help me gain back my SEO ranking.

Hi guys, can anyone guide me how to gain back my SEO ranking?

My domain was expired 18 days ago and I didn't aware of this happening. It was renewed yesterday and now I can't find my page when I search using key words in Google. ( Before this my web page rank 3rd when I search using keyword ).

Even if I type the name of my clinic I couldn't find my webpage as well.

Thank you very much and your help is much appreciated.