Worried that my baby isn't putting on weight

Hi mommas! My dear baby is 2 months old and I'm worried he isn't growing well or putting on weight. At the last check up around his 6th week the PD said he is slightly below the 50th percentile so she recommended for him to drink slightly more and frequent and to burp him well since he spits up alot. Things got better for a while but his spit ups are back again. Just wondering if you guys actually invest on baby scale or am I over worrying and should just rely on doctor's scale at the next check up which would be on August?