What hcg levels are normal?

Tiffany
I had <a href="https://glowing.com/glow-fertility-program">iui</a> done on September 1st, on the 16th my hcg was 230, on the 19th 514, and on the 21st 1,138... is this too high for a single pregnancy? A nurse said I was likely pregnant with twins..... this is my first pregnancy.