I give my baby formula once a day yesterday I didn't give him any because I figures out its not…

I give my baby formula once a day yesterday I didn't give him any because I figures out its not letting him poop and now I'm sitting here and I have to give him a formula bottle because he won't take my nipple without the shield and my boyfriend rushed me out so fast I forgot it :( now I know he's going to have issues I really don't like to give him formula in the first place but what am I supposed to do? I sadly forgot my hand pump also :((