Ditto what Lara said.
You cannot correlate your present pregnancy weight gain, based on your first pregnancy... the reason is, you are at a different starting weight, with your 2nd pregnancy.
I was sorta like you... but I am 5' and gained 25 pounds in my first pregnancy... the weight did not come off by the time I was pregnant the 2nd time. THUS, my Doctor said I could not gain no more than 15 pounds this time around. He monitored my weight more strictly and I had a different set of nutritional requirements to follow... mainly, not eating junk and sweets. IF you gain too much weight, given your CURRENT condition now... yes, it can be unhealthy and/or lead to complications. Remember, your "starting weight" this time around is at a higher weight... so you must keep this in mind and this pregnancy is not like your first in terms of health and weight requirements.
With my 2nd pregnancy, I only gained 15 pounds total. My Doctor was very pleased and said it was perfect.
Gaining weight during pregnancy... too much weight.. is "not" always the healthiest thing... and it has to be relative to your current condition and starting point.
Heed to your Doctor... if anything, have your Doctor explain to you why your weight is being watched and how it impacts your health/pregnancy.
All the best,
Susan