Weight gain concerns 😟😟😟

So my pre pregnancy weight was 163. During my pregnancy I dropped to 159 up until my 21st week. By my 24th week Ive only gained 1 pound putting me at 160. Ive expressed concerns to my doctor considering this is my 5th pregnancy and my others Ive gained an average of 35-40 pounds. He simply told me drink a milkshake every night... Um okay 😕 Im currently 27 weeks, anybody else having problems not gaining weight with pregnancy??