To convey the same meaning, you would need to rephrase it depending on the context. Here are a few options:
* "I've been waiting for weeks." (If you're expressing that something has been going on for weeks)
* "It's been weeks since..." (If you're specifying a period of time)
* "Weeks have gone by..." (If you're emphasizing the passage of time)
Could you please provide me with some context about what "tengo semanas" is being used to express? This would help me give you a more accurate and natural English translation.