Breast milk Q

I'm wondering if diet affects the way breast milk tastes. My 9 week old baby girl was born at 32 weeks. Because she was early and stayed in the NICU for almost a month, she does not latch on to me to breastfeed well. I pump and feed her my breast milk exclusively. She normally eats well, at least 3 oz each feed every 3 hrs. I pump out way more than she eats, so I have lots of milk in my freezer saved up for her. 

This past week has been a little bit challenging. She's not eating as well:  not finishing her bottle, taking longer to feed, and is very fussy during & after. She's been very very gassy, spits up more often and throws up milk sometimes. I'm wondering if there's something wrong with my milk (like it's taste or something). Maybe something I ate affected my milk. I write the date on my breast milk bags, but I can't remember what I ate weeks ago for the milk she gets fed now. Also this all started after she got her vaccination shots at her 8 wk appt. That was 4 days ago, so any reactions from her shots should be over right?

If it's my milk, what foods should be avoided? I love spicy food, so maybe I should hold off on it. I'm a 1st time mom, so any advice or help would be greatly appreciated. I hate seeing her so upset and frustrated lately. Thanks!