When is the right time to let go and to hold on?

When is the right time to raise your hands on love? Sometimes I feel like I can no longer bear things out, I feel like giving up. I was asking myself where did I go wrong? Where did I fall short of? Is there anything I have not done which should be done?

I am losing hope. When is the right time to let go and to hold on? Lord, please give me enough of strength to carry things out.