Greetings, Always keep some distance time gap between two . Any way it has happened for good. Please next time be careful. Since you are pregnant, you have to stop his breast feeds. Please continue Lactogen, Don't chage for any other brand. These infants are very sensitive. Ask some one else your husband or helper to be with the baby and develop friendly withyour child. Teach her how to feed. let her feed the your son. Since he is 5months old you can start banana mash to keep his nutrition good. Slowly go on introducing a new food item ,one at a time .You can give cereals, but remember to start only one item per week and increase in quantity. next week continue current item, and introce a new items. That will solve your problem. But at no cost, BREAST Feeding.It will hamper new baby in your uterus will suffer.

Since you have already started weaning foids increase theyr quantity Dal khichadi Nachni Fruits Veg soup mixed with rice You can kerp on trying to give formula feeds But no worries if he doesn’t want Continue with multi vitamin and calcium supplement

Give formula upto 6m of age according to baby's need. After 6m start complementary feeding with cereal based mashed semisolid diet and continue milk

Keep trying to give formula milk. Increase number of feeds of weaning food like dal rice, khichdi, mashed potato, fruit pieces, sheera upma. Search baby food recipes 6 months. Websites like Tarla dalal give lots of recipes