Mind freeze


when you are like this, just
a) check all forced moves especially the seemingly unreasonable ones, like queen sacrifices
b) try to calculate accurately without missing taking account of tactical motifs like pins
c) change your focus. Like if you are looking for a mate, then focus on material. Or if you are trying to defend, switch your focus to attack. If that fails as well, then do again a and b, since there is obviously something that you don't see, either because it seems unreasonable, or because you are miscalculating something.
I have been studying tactics very hard for many long hours.. now it seems I cannot think at all and even the simplest problems confound me... then when i am given the solution.. I can hardly believe I missed it
Anyone else experience this mind freeze? What did you do do overcome it?
Thanks!