If you're struggling heavily with depression, you should definitely speak to your doctor. Antidepressants are a great measure to make things a bit more manageable while you get things back on track, get therapy, etc.

The napping during the day is almost certainly feeding back into worse night time sleep, which makes you need daytime naps, etc. I would do everything in your power to not only stop taking daytime naps, but also to establish a consistent sleep routine and bedtime ritual. You can essentially train your body to know it is bedtime, and a bedtime routine goes a long way with that. Pick a time you're going to go to sleep every day (including weekends) and a time you're going to wake up (and be awake) every day, including weekends. Treat them as law (within reason) and you should find it easier and easier to feel sleepy and get to sleep.

Consider using a sleep app (like sleep for android). It tracks your motion while you sleep, and can detect (roughly) your sleep cycles, as well as when you're awake. If you set an alarm with a "smart period"(which you decide upon, mine is half an hour) for the time you have decided to wake you up, it will track your position in your sleep cycle and try to wake you up when you're at your lightest sleep, which improves how easy it is to wake up and feel rested.

I know everyone always says "no screens before bed" but like yeah, actually try to get away from screens before bed. Most things we do on screens are very stimulating, which keeps your brain in a more awake, alert state. If you "switch off" an hour before your decided upon bedtime, and go about your bedtime routine, you may find sleep comes a lot easier.

Something that helps me a lot as well with sleep is something I learned from an ex-army chap. While you're lying down to sleep, find your comfortable position, and then, starting with your tongue (which is actually the most important to focus on in my experience) relax each muscle one by one. I find if I don't think about it, my tongue will be basically glued to the roof of my mouth and under pressure. Relax your tongue, then your eyes, your brow, cheeks, face, mouth/lips, neck, shoulders, upper arms, lower arms, hands and fingers, your chest and back, then your lower back, unclench your butt (crass but necessary), your upper legs, lower legs, and feet. As you relax each one, just take inventory and make sure the ones you already relaxed are still relaxed, especially your tongue. If you're finding it hard to "manually" relax a muscle, tense it really hard for 5-10 seconds and then release, it should be easier to just let it relax. This technique is fucking magic I swear to you.

Best of luck to you, internet stranger, and good luck with your mental health journey.