Gaining weight

Michelle
Hello everyone and congrats!  I just left my 9 wk appt and all is great with the little gummy bear, but my Dr. told me I need to gain weight.  Like a lot... 35-40 lbs.  I've always been underweight, and have a terrible time putting on pounds.  Can any of you give me any hot tips or suggestions?!  I'd like to do it in the most healthy way possible for both me and the bean!