Advice Needed: Can i breastfeed and also give my baby formula

Yes

Yes, but if you can breastfeed why not just do that?

Quoting larissalarie:

Yes, it never has to be all or nothing.

There are some important things to keep in mind though: Keep bottles small and infrequent to prevent a bottle preference. Ideally Mom will never be around when baby gets a bottle. A baby can control the flow when breastfeeding and also have to work harder for their meal at the breast, a bottle just drips into their mouth and they swallow it or choke. This can lead to a baby taking a large bottle even though they don't need nearly that much. Taking a bottle after nursing is also not indicative of the baby not getting enough when breastfeeding because of this.
If baby starts refusing to nurse and you want to continue to breastfeed, you STOP THE BOTTLES. Many give a bottle when baby refuses to nurse, which leads to more and more bottles and premature weaning. If you refuse to give baby a bottle when/if this happens, baby WILL eventually breastfeed, they won't allow themselves to starve.

Also beware that bottles, especially in the supply establishing early weeks, can lead to low supply. Every ounce of formula you use is an ounce your body doesn't get told to make (bf is supply & demand, baby demanding it is how your body knows to make it) Now if you always want to give a 3 ounce bottle of formula at 6:00 for example, then it won't matter that your body makes that much less. However if you just want to supplement more sporadically than that, you'll need to pump for the missed feeding whenever baby gets a bottle to protect your supply. Occasionally you might be able to get away with not pumping, but until you know how your body responds and how strong your supply is, it's better to pump and not risk it.
You only need to pump for missed feedings though, otherwise if you're nursing on demand there's no need to pump.

Good luck!

My sister-in-law does. :)