Correct positioning and attachment for breast feeding is very essential. The more you will attach and stop taking stress the more milk will be produced. It's of paramount importance to do exclusive breat feeding for 6 months. In your case you should breast feed first every time then can give the child some top feed with katori spoon or palade as required.

Rather than giving lactogen you should try to get the reason. Most probably your nipples are not well formed or sealin of babies mouth is not proper. You can consult your gym for the same.  Another common reason is nasal blockage due to cold. You can use nasal saline drops to deal with the problem.