LO is 7w and is feeding on expressed BM that was once frozen and suppl FF. When I give her straight BM, she cries and is hard to feed her, but when I mix alittle with formula, she'll take it with LESS fuss. Plus, we've tried 4 different bottles. She used to be on Avent with no problems, then she started eating with a huge mess, mostly milk on her bib. The playtex drop ins looked similar with mess, Joovy made her gag and now we're on Dr Browns - ugh. She was eating fine (less mess) for 7d, then started making mess again, exactly like avent bottles. Its like she's spitting some of it out as she's eating. So, should I make it mostly formula and not BM to see if it's milk? I don't get why she used to be fine with avent and dr browns, and then she becomes sloppy/lazy after a week like she doesn't like the taste of milk. Just curious if others experience something like this.