This is very common especially during cloudy / rainy spells in UK weather. I guess to help counter this is to ensure we spend time outdoors when it is indeed sunny and pleasant. Research has shown vitamin D helps reduce symptoms of depression for example.
Have you tried engaging in activities that lift your mood? I understand the current state of affairs make it difficult to socialize but perhaps doing the little things like keeping in touch with friends even if digital/over the phone can help.. listening to your favorite songs or discovering new music / finding a new hobby for yourself could be things to help lift your mood, my friend
- battle angel