Everyone's mental health (and corresponding path to wellness is different), but:
narsica's four step program to generic mental health wellness:1. See a doctor. Get medication if your mental health affects your daily functionality. Your GP should be able to give you a prescription for an appropriate med for whatever your presenting mental health issue is. Your doc should also do a general physical exam, to rule out an underlying health condition - Note: DO NOT STOP TAKING YOUR MEDS OR ADJUST YOUR DOSAGE WITHOUT SEEING YOUR DOCTOR.
2. See a therapist. If you don't like the first one you see, see another one. Not all therapists are equal, and it's important to find one you're comfortable with and whose methods and style work for you. Cognitive Behavioural Therapy (CBT) is by far the most common, but it doesn't work for everyone. It is important to see a therapist
even if the meds make you feel better. Mental health is complicated, and the most effective treatment is a combination of meds and therapy. If you can't afford a therapist, see if your community has a local mental health center - often they'll offer therapy sessions at reduced rates, or free group programs.
3. Find a physical activity that you really like. Running, yoga, biking, Tai Chi, paddleboarding, whatever. Find an activity that you just click with, and that gets you out of the house and physically active at least once or twice a week (more is obviously better). Finding an activity that clicks with you is great for your mental health - and the physical activity doesn't hurt either.
4. Meditate. Meditation/mindfulness is an extraordinarily useful skill in dealing with stress and anxiety. It can be a simple as sitting in a quiet place for five minutes and consciously slowing your breath. Don't worry about "not thinking" or "clearing your mind". Just focus on what your body is experiencing, where you're holding tension, that
sort of thing. Try doing it for 5 minutes a day, or whenever you're feeling stressed or anxiety. Sit, breathe in, hold for 5 seconds, and slowly exhale. Even 30 seconds of this can make a difference.
The work situation is trickier, as it really depends on the organization and your boss. If you have a really good working relationship with your boss, and you work for a company that has a track record of being really valuing and supportive of its employees, then you might want to consider it. If your relationship with your boss is just okay, or the company you work for doesn't treat people particularly well, then it's probably not the best idea. Some companies offer Health and Wellness programs - access to free, confidential therapy, gym membership incentives, life coaching, etc. So long as the program is confidential, take advantage of it - if it's not confidential, avoid disclosing anything that the employer could use against you.
You could try something with less potential impact. Maybe have a discussion with your boss about moving to a different project, or just mixing things up a little. Sometimes a little change at work is all it takes to jump start more changes in your life.
And if you need someone to chat with, I've certainly lived through my own personal hell of depression and anxiety, as I'm sure many other people here have. Sometimes talking it about it helps.
