Think I might be depressed and I need some advice on how to deal with my feelings

Since roughly around December of 2019 I've just felt like something was always off and there's always something in my life that is missing. Even if I'm happy with everything going on at that time. I feel sad all the time, I have no motivation or energy, I'm so irreatble, I've practically given up on my school work because I don't see the point because I feel like i'm going to fail regardless. No matter what I do that feeling of sadness is always there and it won't go away, my mind is so fogged up with negative thoughts that's its hard to even think rationally.

I have been previously diagnosed with an anxiety disorder and I think because of the long struggle and little improvement I've given up on a lot of hope (I've been in therapy for ages and i don't plan on stopping, but I can't see my therapist because of quarantine) . Also anxiety and depression tend to come hand in hand unfortunately. I'm also constantly trying to support my friends, but I don't always have the right advice to give them. I feel like quarantine is also getting to my friends too because they're getting in arguments pretty often and I'm always stuck in the middle of it all because I don't want to take sides.

I've started to feel guilty about asking for help because I know there are much bigger problems and I don't want to burden others, so I turned here. If anyone has any advice that would be much appreciated. :)

(sorry this is so long, I just really needed to get this stuff out)