I don’t want to claim that meditation is the answer to every mental health problem. But it’s helped me, and I sometimes recommend trying it, particularly mindfulness. (And you can do mindfulness seated and at rest, or walking, or any number of routine activities—just not driving, please!).
I’ve heard a number of people say “But I just can’t still my thoughts! My mind is racing, and I give up feeling more defeated than ever!”
Mindfulness is not about forcing your mind to stop thinking. Rather, it’s about becoming aware of what you’re thinking… and then letting the thought go.
I’ve linked an article I found recently that explains it really well. TLDR (though it’s worth reading in full): A Tibetan Buddhist monk, chosen as the reincarnation of a revered predecessor, absolutely loathed being a monk as a teenager. He was angry, snarly, irritated, and a great vexation to his teachers. Angry thoughts constantly interrupted his meditation practice (and everyone around him).
One teacher gave him some advice: when you meditate, don’t be like a dog; be like a lion.
“When you throw a stone at a dog, what does he do?” he asked.
“The dog chases the stone,” I replied.
He said that was exactly what I was doing, acting like a dog—chasing each thought that came at me…
“When you throw a stone at a lion,” he continued, “the lion doesn’t care about the stone at all. Instead, it immediately turns to see who is throwing the stone. Now think about it: if someone is throwing stones at a lion, what happens next when the lion turns to look?”
“The person throwing the stone either runs away or gets eaten,” I said.
“Right you are,” said my teacher. “Either way, no more stones!… Instead of chasing the anger, grabbing it, and holding on, just be aware. Just be very gently aware of the anger instead of getting involved. Don’t reject it, but don’t dwell on it either. Just turn your attention to look gently at the thought. At that moment of turning inward to just observe, the thought will dissolve. At that moment, just exhale and rest.”
My mind is similar, and my process is just to let the thousands of concurrent thoughts come, put that on a mental to-do list to sort out later and move back to what I was trying to focus on, to begin with. No need to process it all right away. You can think about why you had those particular thoughts when you are not meditating, (if it's something practical like "man I really need to vacuum this floor" you can take care of it), or the next time you meditate you can actually focus on the emotions or maybe memories that popped up if they are important to you to sort out.
I use guided meditations through a podcast sometimes, and I also just do some slow/even breathing and/or walking while focusing on my body and breath. I find it helpful to repeat some sort of mantra or phrase in my head at first in order to get me started when there is no podcast going.