I have no idea what to suggest since I don't know the inner workings of your heart and mind. Occasionally I get into moods where nothing I normally find interesting sounds fun to me, but it usually passes within a day. I think having a depressed or hopeless feeling can sort of filter out the good stuff and leave everything looking bland or repulsive. I personally can't imagine not being able to find anything that interests me and makes me excited to learn, think about, or do it.
As far as introversion and 'recharging; goes, what fills me up and revitalizes me is....
beautiful scenery, looking at photography or traveling or going on hikes with my camera in hand revitalizes me, especially forests and green things - they feed my soul
cuddling, whether it's with someone I love or just pillows and blankets and stuffed animals, feeling cozy and comfortable really helps me to recharge. Also things like putting on my most comfy pajamas and wrapping up in a fuzzy blanket and curling up on my armchair with my warm computer in my lap. I need these cozy times, but hugs and affection especially serve to recharge me. Honestly I sometimes feel like I'm brimming over with energy after a good hug.
stirring, epic, awe-inspiring music, especially music that sounds triumphant will energize me, while music that sounds epic will give me inspiration and generally a better mood and outlook on life, it makes me feel alive.
imagining fantasy worlds brings me a sense of wonder, anticipation, joy, and generally gives me a more positive outlook because it's filling up my mental experiences with things that aren't depressing, with things that are new and different. Much of this effect is also because of the beautiful scenery once again, but I suppose it's also just exploring ideas of other possibilities and just creating. Being able to focus my imagination to bring out details and make it a vivid experience inside is honestly where I feel like I'm 'living' more than when I'm doing stuff in 'real life' and I think it is because it's being creative rather than just taking care of business or going through motions. I really feel like my habit of always slipping into my imagination to dream up beautiful places and create adventures for characters has kept me sane all these years in the face of a relatively predictable and often ugly external environment.
reading a book with characters I really enjoy and with a satisfying ending will often leave me full of energy so I'm bouncing around - because being happy is energizing. Sometimes my love for a character (and also for real life friends) will just make me swell up with bubbly joy. Good movies will do this too.
Thinking about something, or reading about things, that bring me to a better understanding, where I have a moment of everything connecting and making sense definitely gives me a sense of satisfaction in life.