[jays]

This happened to me around 35 as well.

It's important to recognize that you're still young in the grand scheme of things.

A lot of the other comments recommend making friends, having kids, getting married, etc. Those things might help, but can also make things worse. And ultimately, they might not necessarily fix what YOU need.

It sounds like you lack meaning in your life, motivation, and a clear direction.

It's important that you spend some time thinking about what you want your life to look like to create the happiness you desire. What's missing? What do you want to be working on? What will provide you fulfillment? etc.

You might need to go explore some new hobbies or experiences to figure it out, but therein lies the exciting part of life. Try something new and don't be afraid to fail. It's just part of journey.

Once you've got that picture of what you want your life to look out, write it down. Then start making 2-3 year plans to move your life into that direction. This should help get you excited (or scared). Use it motivate yourself to get to your desired end goal.