I am very sorry to learn of this situation. Unfortunately, legal malpractice damages are limited to the actual damages incurred in the underlying case or action. So if you had a breach of contract case and you lost because your attorney made an error, the maximum damages you could recover in a legal malpractice case against the attorney would be whatever it was that you would have won in the underlying breach of contract case. There are no extra damages for loss of sleep, emotional distress, etc. Similarly, in criminal proceedings, the law is based on what the outcome is in the underlying case and is very harsh - the client must prove something akin to actual innocence (their conviction is overturned, or they prevail in some other way on appeal), short of this, a person convicted of a crime cannot prosecute their lawyer for legal malpractice.
Legal malpractice cases are based almost entirely on expert testimony. You must not only find an attorney to act as an expert witness regarding the standard of care for your prior lawyer (to prove the "negligence" elements of the case), but also an attorney expert (and potentially other experts) to testify regarding the underlying claim (you must prove that absent the attorney's malpractice you would have achieved a better result - often termed "the case within the case").
Due to the complexity of these claims, I highly recommend that you retain a legal malpractice plaintiff's lawyer (also called trial attorneys). Fortunately the majority of these attorneys will provide you with a free consultation, and many will represent you on a contingency basis (they will advance the costs of litigation and legal services in exchange for a portion of your successful settlement or judgment).
You can find local attorneys using the State and Local Bar Association directories, or private directories such as www.AVVO.com; www.FindLaw.com; or www.Martindale.com (I personally find www.AVVO.com to be the most user friendly).