It depends on how bad it is. Half of the divorce cases out there involve one or the other party being on anti-depressant medications, so that in and of itself won’t matter much. It really depends on how severe the mental illness is, and how it affects your parenting. If the mental illness negatively affects your parenting, or poses a danger of harm to the children, that will obviously be more relevant. And unless your mental health records are already sufficient for a custody evaluator to assess your mental health, you can expect that a custody evaluation will include a psychological evaluation as well.
You are not obligated to hire an attorney in order to file for divorce; however, having one greatly improves the likelihood your rights will be protected and that your divorce is done correctly. Otherwise, you may end up spending much more on hiring an attorney after your divorce to seek post-decree modifications to clean up anything done improperly at the outset. Having a lawyer with you during this process also lessens the pressure on you during this difficult time. Further, hiring a lawyer is especially beneficial if there are allegations of abuse — spousal, child, sexual or substance abuse — because in those situations, it may be impossible for the abused spouse to negotiate effectively. A lawyer can help arrange the necessary protection for an abused spouse and the children. There are many other instances where a lawyer will be significantly helpful in a divorce, such as: asserting a non-marital claim, complex finances, divorces involving business ownership, divorces involving one spouse living in a different state, and many more instances.
A Motion is a paper asking the Judge or Referee to decide an issue in a case. In a divorce matter, a Motion for Temporary Relief allows you to ask the court to issue a temporary order for child custody, child support, spousal support, and certain property issues. The Temporary Order allows you to get needed financial support while your case is pending in court. The Temporary order will expire when the final divorce decree is signed by the Judge and "entered" by court administration.