Ganb8te, thoughts are things. If you prepare yourself for falling into a funk, you will fall into that funk. Instead, shift your thinking. Prepare yourself to handle the funk, just as it is. Not by faking it, but by BEING it. Be the you who works through the funk, the strong you, the accepting you. It doesn't just happen, you have to practice it. I'm convinced no one is an expert at acceptance. It's a huge struggle and in most cases requires a funk.
Breathe, treat yourself well, do something fun, smile for a minute, and walk through it. Funks don't last forever. By definition, funks are short. And you never get a phone alert that you're on the other side of the funk (that would be so helpful!). Strangely, you actually get to decide how long that funk lasts, to a point. The power of that is immense.
Separating PMA from expectations of positive outcomes is a good thing to work on. We have positive expectations as a way to maintain control. It's almost magical thinking... If I believe it, maybe it will come true. I call it the Santa phenomenon. It's not just glass-half-full mentality, there are expectations there. Expectations of things we have absolutely NO control over.
PMA is, for me, something that comes naturally with some space and detachment. It's an expression of how I feel about my life while my marriage is on a shelf. I laugh, I sing out loud to '80s songs in the car, I polish my nails a color I like even if it's a little funky, I act silly with D, I poke gentle fun at coworkers who return the banter. I had to busy myself so I could stop over thinking and obsessing . Meditation helped here. I was able to observe what I was facing from more of a distance.