Breastfeeding help!!

I am currently breastfeeding and formula feeding my 7 week old but I feel like my supply is getting less, when I don’t breastfeed I would pump and store it in the freezer but my electric pump has broken and my partner has gone back to work this week so it’s my first time on my own with my 3 year old daughter and 7 week old son so its been a very challenging week so I haven’t really breastfed much but now I’ve gotten into a routine with both children I’ve tried to breastfeed more again but now I just feel like my baby isn’t feeding for aslong and he keeps unlatching a lot, I brought a manual pump untill my new electric one arrives next week but I can’t even pump an oz with it, has my supply been affected and what can I do to boost my supply again?