I'm not a neurologist or a psychologist, but I think our brain needs the feeling of success in regular intervals. Otherwise we become stressed, helpless or catatonic. There's this famous experiment where rats that experienced the feeling of drowning for some time would remain catatonic even after being rescued afterwards.
Successfully checking a manga update right after it uploads is one kind of "success" for our brains, as is getting likes for your comments. You have probably consumed so much content on this site in recent time that you no longer feel enough happiness for doing so. Instead you'd probably feel better if you found a way to get away from it. Don't worry if you need time or help, it's a different way for everybody
Edit: Doing drugs is probably not recommended though. They chemically simulate that feeling of having accomplished something, but because you haven't actually achieved anything, you may become addicted to the drug instead of anything real. Becoming addicted to success is much better than becoming addicted to drugs.