Yes, I have experienced it more times than I can remember . I know how you feel. However, it is hard to pinpoint exactly why you are having difficulties without having the ability to see your game in action. From your post, you indicate that it might be due to some sort of mental block. It very well could be. However given your average, it might be due in part to some inconsistencies in your physical game. A 185 average is respectable, but in order to improve on that, requires dedication to practice, as well as getting the assistance from a qualified coach.
I do a lot of coaching, and I am surprised at how many bowlers do not devote time
to serious, constructive practice. On the flip side, I have students who bowl as many as 4-5 weekly leagues. They have no time to actually practice with this type of schedule. Instead, some want me to give them lessons between league frames.
Unless the student is exceptionally gifted (and very very few are), this is impossible.
The important thing is that you are looking for help. Find a qualified bowling instructor in your area and have him/her evaluate your game first. Then, devote time
to practicing techniques recommended by your instructor. You will be amazed at
the improvements you will make as a result.
Best wishes to you and good luck!