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Could be. However luckily if you're not sure if you're depressed then it hasn't progressed very far yet, so try to kick it now before it tightens its grasp. Exercising like you tried is good, so is making sure you eat healthy and take vitamin D and omega3 supplements now during winter. And last but not least cut down on dopamine kicks like alcohol, candy, masturbation, porn, etc if you indulge in that too often.
And it could also just be that you just live a boring life. Try doing something outside your comfort zone. Go on Tinder and role play as a chad, or just see a hooker if you cba. Do some exotic excursion like paragliding/skydiving, kayaking, glacier climbing, shooting range, rent a sports car etc.