HELP!! Do any mom's have to supplement?!?

Elizabeth
This is my second week back to work and I'm worried I'm not pumping enough. I have probably 2 to 3 days frozen and am pumping 12 to 14 Oz everyday at work but some days he eats almost 18 Oz when I'm gone! I'm sure I'm just over thinking but I'm a ftm :/ if you did have to supplement what did you use?? I am interested in similac supplemental formula but idk. I drink water and Gatorade all day long and take milk flow max from upspring a probiotic a prenatal and an omega 3. I pump 2 to 3 times while at work and nurse on demand at home. I feel like I'm doing everything I can to keep up. Any words of wisdom suggestions or just encouragement would be nice :) pic because he's cute :) (12 weeks 3 days old)