I don't have a specific incident that i can recall where things were literally falling apart even though i'm sure there are plenty of moments where they were. I believe i've experienced more of the dramatic type of falling apart where it's mostly in your head; you believe things are falling and it's over but as usual you find out at the end of the day that you just overreacted and all is well in the world.
I think for me the best way to deal with situations when i feel that things are falling apart is to focus on myself and see how i can reverse the situation so i'm not stuck in the free fall feeling anymore. I like being in control of events in my life as much as i can, since i can't control external factors affecting a specific situation all i can do is control my actions or how i react to what's happening. I try to be positive and come up with positive solutions but sometimes it does take a few days to get out of the rut.
Take for example us trying to conceive a baby for close to 5 years now, so far not happening, but from the beginning we decided to never put ultimatums on this process, we did not say we will never try this procedure or the other, nothing is off the table, if we can afford it we try it, we tweak our goals as we go and this flexible plan helped me stay away from the "the sky is falling" scenario.
I guess my advice is when you feel things are falling apart be flexible, be positive and get creative.