Little guy won't wake up for feedings

Hey my little guy has been a great sleeper since he was born Friday afternoon but today he absolutely will not wake to eat. I am nursing and he has not had a good latch and feeding since about 10/11. He had his circumcision today around 1, is that why he is so sleepy? I've tried all the tips i have read online and nothing has helped or worked. I'm concerned about him getting what he needs and it delaying my milk from coming in. Any tips or thoughts?