It's tough, but I've heard from credible sources that after 12 months of sobriety, things should be much better.
Exercise and meditation are my main two.
There isn't any approved drug for stimulant addiction as there is for opioid addiction. But maybe Wellbutrin or Provigil might be something to ask your doctor about in order to see if it applies. They might attenuate the negative impact that meth withdrawal has on cognition, but they wouldn't work if you're still using meth.
Busy busy busy. Don't give yourself time to think about it.
Caffeine of ~300mg or less per day is supposed to be healthy.
Your brain needs to heal. Keep that in mind. Perhaps explore adaptogens like tulsi or ashwahganda (with doc. apporval). The former was a great help to me.
Have a good team of friends/family that you can talk to when things get particularly bad.
If you're depressed or bipolar and are self-medicating, first get sober then the picture will clear up, and therapy will start helping. It's a tough road, but it's the road of the victor.