I am unmotivated. I can't seem to do things like read manga which I normally love doing. I no longer want to reply to anyone. What's wrong with me?

Depression can often cause you to lose motivation in many things, even things that you used to love. There is nothing wrong with you. Things like this happen, and it’s okay. What’s important is for you to try your best find the motivation to do something and enjoy it again. Try taking walks or just going outside and doing the things you think you’d enjoy. It often sounds useless to just do that, and it can be hard trying to motivate yourself to get outside at all, but it really can work and putting things in your schedule to take care of yourself can help.

Nothing is wrong with you. When you feel this way, it is a sign that you've processed a lot and you need a break. Take a break. Relax, refresh then go again. Just like a mobile device, when it overworks, it begins to malfunction. This doesn't mean it has a problem. It just has to be kept untouched for a while then it can be used again. Infact, this is a sign that there is something great inside of you and you need to get enough strength to unleash it. ask space scientists....there is a minimum velocity needed (escape velocity) for a space aircraft to leave earth. Your body is indirectly speaking to you....there's something wonderful in you and before it can be unleashed, you have to rest very well so that you wont break down halfway.

There may be multiple causes for a sudden lack of motivation in doing anything. Have you started projects you can't handle any longer? Do you fear you don't deserve the possible accomplishment your actions would lead to? If you have too much to do and you don't want to come back to things reminding you how much work you have to do, how overwhelmed with uncontrollable things you are, you can meditate, for example, to help you see things through, put them in a different perspective. Other than overwhelming work, lack of motivation may come from disappointment, lack of will, envy, because of routine. Try something new! Try meeting new people! Put yourself out of your comfort zone if you can/want to change your routine (with little changes that is) and see how it turns out!