Under the weather? How about your good days and your bad? Thankfully I haven't been subjected to severe mental health problems, but I do have a friend that pretty much has every trauma event happen to her. She's been diagnosed with borderline personality disorder. The extent of such a disease is huge. Therapists are advised to only take one such patient on board at a time. Why? It's so complex and hard even for a professional to deal with the issue, let alone solve.
That leaves a question for friends of those with BPD. What do you do?
What can you do?
One thing you shouldn't do is try to solve problems. In fact, if you become that defacto person where issues are being dealt with (you're not a professional remember), then you've gone too far. Boundaries need to be in effect when chatting with your friend. It usually takes years of abuse/trauma to get to a place where you're diagnosed with BPD and it will take the same if not more years to get better (if you ever do).
Answers are something we hope for and look for, but in some cases they simply don't come and aren't in the form we'd expect. That's the reality of some severe forms of personality disorders. Be ready for them, it can be daunting.