gaining too much ?

So I don't know how much I weighed before but at the doctors office I weighed 148 pounds at 11 weeks. today I went in and the doctor told me to be careful that I ONLY should gain 20-30 pounds and I weighed 167 at 24 weeks 3 days. do I weigh too much ? do I need to be more careful ? I'm just not sure what to do it's my first pregnancy and need advice I don't want to have to have a c section or never lose the weight