I believe that in cases like this the best thing to do is to address internal fragmentation.
What does it mean and how to do it?
The reason why you feel like you breaking from the inside and weak is that inside of you there are many aspects of you who have not been addressed, taken care of, paid attention to, i.e. suppressed. When we ignore our inner aspects over a long period of time, those parts of us start to “ask” for attention louder and louder and eventually creates a crisis, so that we could not ignore them anymore and finally resolve this inner conflict. The feeling of weakness also comes from the same root - there is no “solidity”, foundation, support, one direction internally, hence the weakness.
Chances are that by now you have created a life that is not really nurturing you, therefore to cope with it you needed to put up a “front” for some time, hence the point above (i.e. ignoring other aspects of yourself created a crisis). Probably your environment is not supporting you in the way that you need to be supported (including those suppressed aspects of you) and therefore now it is coming to the point of crisis that you are noticing that things are really not right
The cure for this is to START addressing your inner fragmentation and get onboard with your best interests. And I mean on board with the best interests of the TOTALITY of you. Steps for that are a) start to get to know your inner aspects, especially those who are most in pain, most tired, most weak, most neglected, and b) start to create a repair in your life by changing your priorities and behavior in a way so that you don’t bulldoze yourself and your own needs.
Start to be your own advocate: practice self-acceptance and validate your needs. For example, if you are identified with “being a strong man” but there is an aspect in you who feels weak, you need to accept that aspect as part of you: “yes, I do have a part in me that feels weak” and if that part needs something (i.e. “I feel really weak right now, I need rest”) understand that it is important to listen to it and to make adjustments so that the totality of you feels better.
This subject is really wide and there’s loads of material to it, if you want to know more you can read these books:
“Embracing Our Selves: The Voice Dialogue Manual” by Hal Stone and Sidra Stone (mainly about inner fragmentation and how to deal with it);
“Fear of life” by Alexander Lowen (explains well emotional crisis and why it happens).
I'm sending you my wishes and hope that you will be able to go through whatever difficulty you are facing right now and once you get out, you will find yourself with a more solid and strong core inside of you than you have ever experienced before.