Can low dopamine in the brain cause irritability, memory issues, emotionless...? Remedy?

IT'S COMPLICATED. The mechanism of action of brain dopamine is not full understood. Low levels are associated with Parkinson's disease and probably ADHD and restless legs syndrome. Your symptoms may reflect depression and there are medications that can increase both brain dopamine and serotonin levels. Pounding heartbeat and tachycardia may be symptoms of panic disorder. You should get a psychiatric evaluation.
Yes. Low dopamine, which is often a consequence of methamphetamine addiction, causes a depletion of dopamine stores in the brain. This results in severe depressions as a withdrawal. These depressions include severe irritability, extreme fatigue, emotional blunting and lack of drive. Thinking problems can also occur.