mixing formulas, Bad Idea?🙄

Jackie
My 6 month daughter drinks enfamil formula that is given to me through WIC but she only gets 4 cans because I am also breastfeeding but it's not enough because my milk supply has gone so low ever since I got in a huge arguement with my SO, so when she finishes her 4 cans I have to buy 1 or 2 cans but I don't get enfamil I get CVS brand and I give it to her. My concern here is would that get her sick? I am breastfeeding her when I give her solid food and 2oz of breast milk too.Â