Ok, so we are 6wks BF & going fairly good.....so far only given 40ml formula once. I don't want to give up this time!!!

The thing is it seems some days I don;t have enough. I know about extra feeding for growth spurts etc. But DS2 has several days each week where he just feeds & feeds & doesn't sleep. It seems 5mins after a feed he's hungry again. But he doesn't seem to be gulping or swallowing??? then he's up til late that night too. Then a day or so later i'm soooooo full he just feeds and sleeps. Could I have a low supply & if so what can help?