Is t possible to bring my milk back?

Su
I started supplementing my newborn in his second day of life as he was born via planned c-section and my milk came in the 7th day after birth. Then I've been pumping and formula feeding him until I progressively ended drying up in the 5th week (a week ago) He has been having wind and constipation issues almost since his second week of life and getting worse and worse and I can't stop thinking that this is all my fault because I didn't try to breastfeed him harder. I've switched formula, bottles, all kind of remedies like Infacol, Gripe water etc.. take him to the doctor and he only prescribed suppositories. Nothing works and I seeing him in discomfort makes me cry. What can I do? If I pinch my nipples I still get a few drops of milk, is there any way I can bring my milk back and start again? TIA