She is constantly wet and she only poops maybe one every three days and they are big blow outs. And also what is more milk plus?

Why do you think she isnt getting enough? Unless she's still constantly asking for food after a feed she's likely fine. The body know what to do, and even if the breasts don't look full they are still often producing plenty 

The best indicator on whether baby is getting enough is weight gain and output. Is baby gaining weight? Have plenty of wet and poo diapers? If yes, then you're providing enough, no need to do anything. With that said, try paying attention to when she's the Fussiest... Like after you've had dairy,veggies,etc. And avoid those foods.Pump after you nurse, if you barely get anything then baby is draining your breast appropriately. Pump in the morning when baby is asleep still, pump when baby naps, and once during the night. You can try fenugreek, blessed thistle, mother's milk tea, brewers yeast, lactation cookies, more milk plus, power pumping, etc

My son gets super fussy but he swallows a lot of air when he eats which causes gas. We introduced a pacifier to soothe him at 3 weeks and that helped. We also started doing massages to relieve some of his gas. 

Do you have a lactation consultant..

My baby boy was born 2 weeks earlier then my due date. So I didn't have my milk yet. I used Enfamil supplementing formula maybe one or two feedings. I also only did maybe a once of formula and let him nurse of he was still fussy after.You can also pump one breast while letting him nurse on the other. This stimulates both breast for a better milk build up.If he starts to have spit up a lot you can also try Enfamil infant AR. This has helped him with his spit up problem. So if you do introduce formula do a little at a time so it isn't so hard on his stomach since you are breast feeding. 😁 I hope this helps you a little.