Baby bottle or Formula?

Hello mommies out there! I would like to ask, share and seek help from every mommas here on the app. I'm a first time mom, my son breastfed on me for two mos but because of latching problem(both of my breast has inverted nipples, I tried nipple puller but it doesn't work at all) we decided to bottle fed our son(but still with my own milk) , it's a hard decision of us esp me. I'm so stressed out that time 'coz I do promised myself since I'm pregnant that no matter what it takes I will push to breastfeed my son. I do use breast pump, it was great not until my milk supply suddenly decreases, I drink lots of supplements and included my diet all foods that increases the production of milk supply but that thing didn't work at all. I'm stressed and frustrated that my son will not be able to drink my milk anymore and can't accept the fact that he will be consuming pure formula soon. His pedia knows about this, then we go on mix feeding coz my own breastmilk isn't that enough. I'm mix feeding until my breastmilk was totally gone so he's consuming pure formula now which is prescribed by his pedia. Now my little one is turning 6 soon. Then I noticed that his consumption and appetite on consuming his milk wasn't the same as before. He can consume 32-40 oz per day but now he can just only consume 25-28 oz. My own mom said maybe he is teething, but i can't see anything new on his gums. Sometimes I think its his formula? (Enfamil A+) But my husband suggested the baby bottle was the possible reason of the problem. We used Avent wideneck bottle since he started to feed on the bottle, so last week i purchased a lot of different baby bottles (wallet is crying) i tried a lot of bottles but he doesn't want it and at last I tried Pigeon Wideneck bottle and I feel like there are changes. What do u think mommies? The formula or bottle? #pleasehelp #1stimemom #advicepls #firstbaby