How to start pumping

Okay ladies, my little man is 3 weeks old. We have a road trip this weekend so I’d like to start pumping just a bit to have some bottles on hand for it. I’ve been nursing him constantly and eating everything under the sun to increase supply along with a gallon of water, Mother’s Milk tea, and a Gatorade. However the only time my boobs fill full is in the morning so I’ve been pumping between feeds. I managed 2 oz this morning from both sides and another ounce just now around 8 pm. We might be into a better sleep schedule so he’s finally going two-three hours between feeds and not constantly snacking and catnapping.

I feel that if I pump, he is going to want to eat that because I won’t have more ready. If I pump to relieve some pressure in the mornings, it’s all foremilk. If I try to pump after he eats for the hindmilk, I don’t feel as if there’s anything left.

When should I pump? Is 3 ounces enough at 3 weeks? How many times should I try to pump?