Depression will make you want to be antisocial, but positive social situations are good for your mental health so sometimes you have to force yourself into it. Exercise is very good for your mental health, and I think part of your issue is working from home. Take vitamins because many people are deficient in them — B will give you energy, C better immune system and D will help with your mood and sleep. It is good that you have pets, because they are company.

I would say that hobbies are a good shout. Especially those that result in the production of something physical whether it is a knitted item, a wooden thing or whatever. Also very good to take up a musical instrument. I was put off music for decades but am finally playing something.

Online socials are no real substitute for meeting in person. I've learnt that the hard way. If you want socialisation, then consider night classes (especially spoken language since they are interactive), writing groups, and joining societies. If you are religious, consider joining a congregation (mileage may vary so shop around), if not there are atheist groups that do meetups and secular sunday services etc. If you need to, take the initiative and start up your own group. I have done this for nearly four years now and it is still working well.

Get out into nature, not just manicured parks and artificial environments.