In my opinion, due to your schedule it’s very hard for you to slot in 3 hourly pumping which caused your supply to drop. As our milk works on demand and supply, I don’t think anything will help now (unless you’re oversupply from the start which is not the case). Dropping pumps/latch sessions signals your body that you don’t need that much milk.
The only way is to not skip pumps and drink more water. Take supplements if you feel it can help (I take legendairy milk supplements). Also, stress will cause your supply to decrease as well. If your baby is sick, you can offer breastmilk instead of not latching/pumping out for her. Our bm has antibodies to help them. What I can advise is, give what you have then top up with formula. Don’t stress too much. Good luck!