If you've been feeling like this for a while, but kept on doing it, ouch. There are lots of projects who will be happy to help you 'exit' - if you say roughly where you are, it should be possible to point you in their direction.
If this is a sudden thing, then it's possible this could be temporary. There's at least one thread here about dealing with feeling burned out.
Either way, it's a sign you need to look after yourself a bit more, whether that's by quitting, taking a break, being more selective about who you'll accept as a client, or...