You sound like a deep thinker. I don't want to contradict any advice you've had from therapy, so only take heed of my ideas if they seem compatible with professional opinion.
Firstly, get yourself out in nature. Take your family or a friend on a long scenic walk - park, wetlands, lakes, bird sanctuary, gardens whatever. Do this a lot as a weekly must-do activity.
On a similar theme, if you have a friend with a dog, ask to accompany them on their walks.
Do you work? If not, gain some purpose by becoming a volunteer. Just a couple of hours a week at a food bank or primary school can give you a great feeling of satisfaction.
Treat yourself to a daily lovely thing. If you don't have money, it can be very cheap - a home manicure that you do yourself for example.
Lift your mood with a trip to the hair dresser.
Exercise to get the endorphins flowing - swim, jog, walk etc. two or three times a week.
Immerse yourself in uplifting fiction. If you're not a reader, take our a free trial Audible subscription and let someone read to you.
Take up a new sociable hobby - dance is good and there are always beginner groups available.