Wow, at 3 months old, that's pretty rough! That sounds awful for *any* baby, but she's pretty young to have an ear infection. A couple of ideas - take what works and ignore anything that isn't for you!:
First, babies who get breastmilk generally have fewer ear infections than those who are on formula (generally true, I'm sure there are exceptions, though!) -- so, if you're supplementing with formula, or exclusively formula feeding, you can always try to re-start breastfeeding or giving breastmilk in a bottle. In most cases, it is certainly possible to increase your milk supply or get the baby back on the breast. Even moms who stopped nursing within the last 3 months still have some milk and can relactate (http://www.kellymom.com/bf/supply/relactation.html)! Breastfeeding for 6 months also reduces the risk of pneumonia for the first TWO YEARS of life (http://www.medpagetoday.com/Pediatrics/Parenting/tb/2634). Plus, breastfeeding lowers the mother's risk for several types of cancers (breast, ovarian, cervical) so it's beneficial for both baby AND mom. That's just the tip of the iceberg - you wouldn't believe the hundreds of other benefits of breastfeeding! For more information and local, in-person mother-to-mother support, you can contact your local LLL group leaders:
Sarah ###-###-#### ____@____.com
Jane ###-###-####
Gwen ###-###-#### ____@____.com
http://www.lllusa.org/web/LivoniaMI.html
Second, if you don't want to or if you medically cannot breastfeed (and this is rare, but does happen) and formula is the only option, you may want to consider temporarily switching your daughter to a soy-based or, even better, hypoallergenic formula since cow's milk formula can increase mucous production, produce cold-like symptoms, etc., in some children. Your daughter may be fine w/ cow's milk formula, but switching to hypoallergenic for 2-3 weeks would allow you to see if there was any change (indicating a permanent switch might be good) or no change (indicating she's fine on the cow's milk formula).
Hope your daughter is better very soon! Best to and your little one - I'm so sorry she's hurting, and I know as a mama that it's not easy to watch your baby suffer in any way. Speedy recovery!