If I lost my case because my lawyer did something incorrectly, do I have a claim?

Absolutely. Lawyers are no different than doctors or any other professionals. They have a duty to perform at a certain standard, and if your lawyer did not perform at that standard, and it caused you to lose your case, you have claim against him. It’s called legal malpractice. Lawyers, like doctors, have professional insurance and if in fact your lawyer caused you to lose your case, because he failed to perform as he should, then you do have a claim against him.