This phrase is used to explain your current situation. It can be used to talk about your feelings. For example, when talking about a child who's getting into a lot of trouble:

I'm at the point where I just don't know what to do any more.

Or it can be used to talk about your current situation when working on a project:

We're at the point where we're going to need to start hiring extra people to keep up with the workload.

But the phrase "I'm at the point where ___" is only used for talking about things that take place over several weeks, months, or years. You wouldn't say "I'm at the point where I'm hungry", for example.