If she is not feeding for longer time , I think you can increase the frequency of feeding sessions. My baby feeds only for 5 minutes. It's enough for her.but she gets hungry in the next 1 hour or 45 minutes. So I feed her again. That's how it has been during the first two months. Also you may check the number of times she passes urine. If there's a good number , then you may know that she is drinking enough.
If the.milk supply is less , you can definintely increase the supply by drinking two glasses of milk every day , drinking lot of water, include green grams and also broken wheat porridge.these two are very effective.