A therapist treats what is happening in your thinking, your mood and your body at the same time: low mood, worry that will not switch off, panic, grief, trauma, anger, and the strain that comes from work, money, family or racism. Most are licensed counselors, clinical social workers, marriage and family therapists, or psychologists. They talk, teach and set homework. They do not prescribe medicine, which is a psychiatrist's job.
Book when something has lasted more than two weeks and is costing you sleep, work or people. Book earlier than that if you want to. You do not have to be in crisis to start, and you do not have to arrive with the words already sorted.
Bring three things. A plain list of what changed and roughly when it started. The name and dose of anything you take, including anything a relative handed you. And one question for the therapist rather than for yourself: how many Black clients they see, what they know about racial stress, and what they would do if you raised it in session three.