Frankie Muniz Calls Last 6 Weeks of His Life A 'Nightmare'

Frankie Muniz says the last couple months have been nightmarish ... implying this is his rock bottom.

The actor-turned-racecar driver detailed his struggles in a social media post Friday ... explaining, "The last 6 weeks of my life have been a nightmare I'm praying to wake up from."

Frankie says life has felt heavy and unclear in recent days ... but, thankfully, it's caused him to engage in some real self-reflection -- to look at areas of his life that need work if he wants to continue to grow as a person.

He writes, "I read that sometimes hitting rock bottom is the thing that wakes you up. It forces the changes you needed to make all along so you can live the best life possible. That idea has been sitting with me."

Frankie says ... "In five years I believe I'll look back at this exact low point and feel grateful for it, because the high I'll be standing on then only exists because I went through this."

Don't get it twisted ... Frankie says this isn't the end of his story, and he's not broken ... he's just being rebuilt -- and he's encouraging others who are stuck in the same boat.

As we reported ... Frankie and his wife of 6 years, Paige Price, announced they were separating over the summer -- then the two shared a video of them dancing together after the split, which went over like a lead balloon with fans.