憋不住了怎么说英语

"I can't hold it anymore" or "I can't hold on any longer" are both ways to express the idea of not being able to hold something (such as emotions, urges, or secrets) in English. Here are a few other ways you could say it:
I can't contain myself any longer.
I can't keep it in any more.
I can't hold back any longer.
I can't resist any longer.
It's worth noting that these phrases are all somewhat informal, and you might choose to use more formal language depending on the context in which you are speaking.