Tips for maintaining a positive mindset?

I have a really weird answer that works for me but might make things worse for others. When I am having a really bad day, I think of stuff I have to do that I hate and will put me in a bad mood that I've been putting off for a while because I didn't want to ruin my day with it. And then do it. All the stressful, scary, annoying things on my to-do-someday list I do when I already feel stressed and the cortisol is gonna stay with me for a while anyway. And it helps me feel good about finally getting it off my to-do list and the adrenaline rush I get from so much crap in one day, it kinda works to lift my mood.

Other than this solution, exercise helps me. Specifically really challenging (either heavy/hard on the body or technically complex) stuff. My mind just goes blank and afterwards there's no space for bad feelings.

Now the combination of these two solutions, in the order written, that really helps.

I hope you can find something that works for you. Maybe this is not it but there has to be something

Well, there's a difference between having a negative mindset and having unpleasant emotions in response to legitimately negative experiences.

If you've had a legitimately awful day, you just need to have those unpleasant emotional reactions for awhile. Having those feelings isn't a problem to solve. They're just something to recognize, respect, and move through.

Learning to be okay with your feelings sometimes feeling awful is a huge part of being able to cope with life, and absolutely critical for maintaining a positive attitude.

I'm generally an extremely positive person because I learned to make space for awful emotions and not react to them as a problem to solve.

If they're rational and proportional, then they're normal and allowed to be there.

Being positive doesn't mean always feeling good and always being happy. It means always being able to experience the legitimate joys and positives in life and not perceiving life as worse than it is.

If you have a legitimately positive attitude then when things feel awful, the instinct isn't to push away the awful feelings, it's to understand the source and proactively start improving the circumstances that caused the suffering in the first place.

So because I'm a very positive person, if my job is making me miserable, I don't push myself to be positive about my legitimately awful job, I start considering different job options.

I'm able to deal with negative feelings because I know that when push comes to shove, if something is really bad, I'll take the necessary steps to make my life better.

So if your day was decent, and you feel miserable, then you may need to work on your attitude. But if your day was legitimately brutal and you feel awful, then positivity in the absence of proactivity can actually be toxic, and just keeps you in a bad situation longer.