Only you can be the judge of why, probably. Try to determine what might be different over the past few months that could contribute to the difficulty. Pay particular attention to soil/root system situations.

Sometimes, the very act of growing bigger causes problems! Has your plant worn out its welcome in the space that you have planted it? (Above and below ground, though I am thinking of below ground, primarily.)

It would be extremely helpful if you described the problem, as best you can. Perhaps the precise symptoms can be matched with a causal agent! 'Looks so sad' just won't work!! lol