After sitting with the feeling for a bit, here are some ideas that come to mind:
1. Maybe we should ask why we feel shame/guilt in the first place. Is it "normal" to feel this? If it isn't we should not rely on it for our happiness (or productivity).
2. What is the value of productivity? Why does it make us happy?
For me, guilt/shame is something to be overcome, not used as a tool. And the value of productivity is something that has been handed down to us by a culture which we've been thrown into. And (at least for me), it's our duty to question these ideas instead of merely giving into them to self-reinforce themselves.