Scared For My Wife (Psychotic Break Imminent?!)

Short version is wife's family is plagued with mental disorders from a nervous breakdown which led to a blackout for 6 months (woman remembers NOTHING of her nonchalant but comatose days after her house burned down), a couple who hear voices (one suicide, the other simply collecting disability and moving annually when the neighbors "start talking about me"), and then a cousin who decided he was actually a woman out of nowhere and within a year had killed himself.

Last weekend I was out of town for two and a half days, I returned and everything seemed a little cool between us but kids were happy to see me. It was late so we got ready for bed and I put the crying toddler to sleep and came to bed to find wife crying. She told me all weekend she didn't hear voices but had persistent thoughts/images of "horrible" things and she was scared she was going crazy, she is about the right age if family tradition holds.

I talked to her and assured her I love her and I was sure she was just over tired and emotional (she hadn't slept well, she never does when I'm gone, plus she's pregnant and hormones are crazy with that I think, right?). An hour of calming and reassuring talk, some snuggling, etc. and she went to sleep and the next day felt lots better. I want to hope that is all it was but this isn't the first time she's expressed concern that she is losing it. What if she is? How would I know until it was too late? is there a time when it's "fixable"? I mean, we go to counseling but our counselor seems like kind of a doofus and I strongly suspect has no idea what to do if she does go crazy.

I'm scared, and worried and its nowhere NEAR the kind of thing I can talk to a person face to face. Can online help? I don't know, I hope so. I love her so much, I secretly worry some days I might come home and find she has hurt herself and the kids..which is dumb but what if its not?!