building milk stash????

im exclusively pumping because bf my son straight from the boob has been a complete hassle and he absolutely hates it.. ive had to give my son formula a few times because i was in the hospital again after i was released and it was kinda hard for me to feed or pump.. im going back to work in about 7 weeks and need to build up a stash before i go back... i also plan on exclusively pumping for as long as i possibly can so if anyone has any tips for that so i can keep it up 😫😫😫