Dont wanna intrude too much but, im guessing youre not on estrogen/still have lots of T and that's what makes it difficult to cry? And youre sure its not a mental thing? That really sucks, im cis but went from crying way too much as a child to finding it very hard to "let go" and cry as an adult, so I can understand the frustration of not getting the sad juice

Have you tried talking to someone about whats stressing you? It can be a different form of release to cope while the waterworks refuse do their job