How do I make this clear on my profile?

I read your profile. In About you section, you clearly wrote that you have 2 huskies and included a note about small dogs. However, some pet parents will not always read profiles closely. So, maybe after your statement I can handle it all, write another couple sentences such as: You are happy hosting large and medium dogs at your home. For safety reasons, you offer house sitting, visits, and walks for small dogs (as well as medium and large) at their homes.

On your Profile under Services & Rates click Dog Preferences. You can specify there what size dogs you can host. Once you do that, technically your name should not even come up when people search for a sitter for their small dogs.