I'm a mental health professional (PhD) who works with founders and tech folks.
There's a lot of good content here already.
Strategies to prevent mental health struggles: regular exercise, prioritizing sleep, time with friends, a pet, reasonable nutrition, a life philosophy that includes self compassion, breaks from work as well as time to deep-dive into meaningful work, self-reflective practices (like journaling), having a relationship with a "wise" person (therapist, clergy member, mentor, etc), volunteering or finding a way to make meaningful contributions to other people. Many of the other things people have mentioned.
Strategies to cope with mental health challenges include extra doses of all of the above plus a mental health professional who "gets" you. Who doesn't have an agenda beyond understanding you and supporting you. I admit it can be hard to find the right therapist or physician but it is worth the effort. Most problems do not require medication (bipolar disorder and schizophrenia are notable exceptions- they are almost always treated with medication)
Most HN readers will do well with someone who is tech savvy and has experience working with folks in the tech industry.
There's lots of great advice here- especially regarding the importance of being connected to other people and taking care of yourself physically (sleep, exercise, diet). Those are the most basic things to tend to when you're feeling off.
I'm a psychologist who works with founders (zenfounder.com) and I can assure you that you are not alone in feeling off your game, even when the business is going well.
Sometimes the answer to the question "why am I feeling this way?" is really hard to come by. It might take some time to sort it out. I'm really glad you're talking about it here. That's an important first step.
It may be a good idea to see your physician and check your thyroid and testosterone levels. Both can wreck havoc on motivation and can affected by sleep-wake cycles (ie. why you feel so low in the morning). A psychologist or therapist can also help you sort out whether you may be experiencing depression or burnout (low motivation is part of both).
Being successful and having a great life don't also protect us from physical problems or from depression. Its a good idea to see a professional to check out a variety of possible causes.
If you have a clean bill of health, then it might be time to ask some existential questions: Are you bored? Is your work meaningful to you? Are you as connected as you want to be to other people? A therapist, coach, priest, or good friend may be able to talk you through some of these questions.
Feel free to reach out to me directly if you'd like more ideas or resources.
What you're feeling is so very common among solo founders. I'm glad you're talking about it here. It is one of the most important conversations founders need to be having. Isolation has the power to undo you and your business.
Like others have said co-working, masterminds, volunteering- those are all helpful ways to connect to other founders. We at https://zenfounder.com/ run ZenTribe groups for founders. Our groups are small and co-facilitated by me (a psychologist) and an experienced founder. There's also https://mastermindjam.com/ which helps people find a mastermind.
Smallish conferences are a helpful way to make some friends that you can keep in touch with: https://rhodiumweekend.com/ and http://www.microconf.com/ are oriented toward connecting people and encourage people to form masterminds.
It's so important to reach out. Don't stop trying to figure out how to get connected.
There's a lot of good content here already.
Strategies to prevent mental health struggles: regular exercise, prioritizing sleep, time with friends, a pet, reasonable nutrition, a life philosophy that includes self compassion, breaks from work as well as time to deep-dive into meaningful work, self-reflective practices (like journaling), having a relationship with a "wise" person (therapist, clergy member, mentor, etc), volunteering or finding a way to make meaningful contributions to other people. Many of the other things people have mentioned.
Strategies to cope with mental health challenges include extra doses of all of the above plus a mental health professional who "gets" you. Who doesn't have an agenda beyond understanding you and supporting you. I admit it can be hard to find the right therapist or physician but it is worth the effort. Most problems do not require medication (bipolar disorder and schizophrenia are notable exceptions- they are almost always treated with medication)
Most HN readers will do well with someone who is tech savvy and has experience working with folks in the tech industry.