Can anyone relate to this...to feeling like you can't trust your feelings and thoughts when you're making decisions?

Absolutely. I have very similar experiences in that I have moments where I'm happy in the moment but anything small can suddenly flip the mood straight back to depressed. It's like one moment the world is good, I accept its negatives with its positives & feel able to tackle them, next day I'm despondent again. So I constantly have people say I can't commit or I'm flaky because one day one thing seems like a great idea the next I'm like wow wtf was I thinking? My mood doesn't necessarily always shift throughout the day quite like that, it's more if I'm in an in between mood, I'm quite volitile, like I haven't decided my mood yet & any small event can flip it one way or the other in an extreme way.

I've been questioning things too but actually more my relationship than anything else. Like I feel like I'm slowly pulling away, not enjoying time spent together as much, just not feeling that strong connection anymore, if anything I feel somewhat trapped. But I'm just not sure if this is my own issues being projected onto our relationship? I'm constantly unsure of how I feel in relation to moods etc, it comes back to not being able to trust my own thoughts & feelings in relation to decision making because they change depending on my mood. I don't want to throw away a previously brilliant relationship as a result of my own emotional turmoil. Or is it the relationship that is the root cause of my own disillusionment with life?

I really have no advice because I feel like I have the same kind of problems that I can't solve haha. I suppose keep giving it time as that's what I'm doing in hope I will be enlightened one day. ((Hugs))