Lots of positivity given, not many facts about depression to be of any possible help. Bandaids only.
Depression CAN last a lifetime. And for many it does. But not for everyone. Depression can be caused by different sources. Not all are directly mental. If you're able to see a general doctor talk to them about being tested for physical causes of depression. Hormones, low vitamin levels and even food allergies can be potential causes and they're good to have checked and ruled out first before seeing a counselor.
Another good option, especially if depression isn't chronic for you is sleep, diet and exercise. It may sound cliche but these three things can be problems. Being on a regular sleep schedule, if possible sleeping at night, is both physically and mentally healthy. And not just on a regular schedule but also getting enough sleep. Sleep is when your body heals and your mind processes the days events helping to better clear your mind for the next day.
Eating healthy helps the body stay healthy and that can help ease your mind as well as also help it be more clear.
Exercise helps release frustration, anxiety, built up energy as well as aids in improving your physical condition. And releases endorphins.
If I had to guess depression may not be a constant thing for you, but is something you can slip in to easier than most. Putting these things into practice can help limit that.
Talking is a help, but it has to be done right. Bear in mind the things you're most likely to talk about are Symptoms and not root causes. Kind of like taking pain meds for a broken leg, but not wearing a cast.
If you feel there's no one you can go to to deal with the core issues I'd still encourage you to keep talking. Not expecting it to make any drastic change but to aid in preventing things from getting worse. Getting things off your chest is mentally and emotionally healthy.
Anyways this is my advice, a chronic depressive for 30 years.