5 week old feedings

My baby girl will be 5 weeks this coming Monday. It’s become apparent to me that she is always hungry! She is formula fed with similac pro advance. Since she has been a month old I’ve been giving her 4 ounces per feeding. I’m so lost on what to do because she is hungry within an hour of eating all 4 ounces. I started putting small amounts of rice in her formula but that doesn’t help either. Everything I have read online says to feed a 1 month old 4 ounces every 3-4 hours. Please give me advice or help me understand why my poor baby acts like she is starving! I give her gripe water and/or gas drops when I feel she needs the extra help, she’s super gassy.