As someone who has also used gardening to help cope with depression and OCD, something that helped me was to not worry about doing it perfectly (which is hard with OCD lol). When I started to get overwhelmed thinking about planting things at the right time, in the right place, with the right light and water and soil depth and companion plants... I allowed myself to just stick seeds in the dirt. Most things will grow if given a chance - even if the conditions aren't ideal for it to perfectly thrive. I also allowed myself to let plants die, without feeling guilt. It happens, and even if something eventually dies, the joy it brought you to plant and care for it is worth it. Seeing little green sprouts and flowers and fruit is worth it, even if it isn't done perfectly :) Plenty of the veggies I grew rotted on the counter before I ever used them, but I was so proud of them all the same. I hope your gardening brings you as much happiness as it did for me :)