I'm 5'6", ride a 52cm Madone, had a professional fit and moved up from 40cm to 42cm bars. The wider bars felt good from day 1, for me.

That being said, your comfortable position may not be the same as me. Go back to the LBS where you got your fit, explain how it feels, and let them fine tune you. If it's a good LBS, they'll help you dial it in correctly. My fit told me I needed a 80mm stem but I felt like I was stretching in order to reach the hoods. Went back in and swapped it out for a 70mm and felt perfect. As the stem was essentially NIB, they just swapped it out for me. Note that I'm not suggesting you change your stem, but just passing along an example of how we had to dial in my fit with an adjustment...

You paid good money for your fit; make sure that you feel comfortable with the outcome.