5 weeks baby formula feeding?

My 5 weeks daughter is formula feeding 4.5 oz every 4-5 hours. Before a week I gave her every 2-3 hours same measure , she was constipated. Ped. said that I was overfeeding her. Now after feeding , she sleeps for 2.5 hour and starts crying and takes her hand in her mouth like she is dying for milk than I wait 2 hours until 4-5 hours are done. I don`t know now , should I go with PED.s schedule or feed her more often.