You've gotten a lot of good advice already. Hot Rod was 1.57 when we got him at 15/16 weeks! He felt like a bag of bones and I was so afraid that I would hurt him. Hubby had to give him is first bath as I was too afraid too. He got his first bath in the bathroom hand sink and even then hubby had to hold him so he wouldn't drown. It took forever to hit that 2 lb mark.
Now he's a very solid 4 1/2 lbs. Very study and muscular. So there is hope.
Hang in there.