Well typically you should gain weight evenly throughout your pregnancy, I think. So, based on your current weight gain you're gaining about 4.5 pounds per 10 weeks. The baby should grow at least another 3-4 pounds in 10 weeks, and depending on if you have already started producing milk and your boobs have gotten bigger you may gain another 2-3. That means you should expect to gain about 7 pounds in the next 10 weeks IF YOU DON'T GAIN ANY.
I"m not sure why you gained 60 pounds with the first baby.... are you exceptionally thin to begin with or have you been diagnosed with gestational diabetes or have any other medical issues?
What does your Dr say about your weight gain?
Those are really the 2 things to be concerned with.
If you are really eating healthy (ie some people will think they are eating healthy but sauces are hidden with fat and sugar or they are eating salads like I eat salads... with blue cheese dressing and crispies on the top....lol) then your body is gaining the weight that it needs. So, look at your diet and make sure you are actually eating healthy. Your Dr can refer you to a dietician who can go over meal by meal with you and make sure you are eating the right foods.
Then - just get back into your exercise routine after you feel well enough post-delivery.
Congrats though - and good luck.