Is a non-compete this broad actually enforceable?

I work for a petcare company as a dog walker. When I joined the company, I was asked to sign a non-compete, despite the fact that it had not been mentioned until I came in for my training. I have been very dissatisfied with my experience with the company, and now wish to leave. I am potentially interested in doing dog walking independently (not using their client list or anything) or working for a pet daycare company, and am wondering how enforceable their non-compete is.

The contract states that I cannot work in any kind of petcare that is at all related to what they do - no grooming, no training, no pet daycare, no boarding, no walking, no pet sitting - even though I only am a dog walker, and am not involved at all in the other parts of their business. The contract extends for 18 months past the date of termination.

The reason I'm curious about this is that the contract seems extremely broad - it in effect bars me from all forms of animal-based income. Since this is an industry I am interested in continuing in (though not with the disorganized company I am with), I am hoping to get out of this contract.