We all have moments when we don't enjoy being with our kids, or don't enjoy BF- and that doesn't make us "bad moms." It just makes us human.
How much lecithin are you taking, and how long have you been taking it? You might need a higher dose and/or a little more time before it starts to work. Have you seen the kellymom page on plugged ducts and mastitis? You might want to try some of the "antibiotic alternatives for treating mastitis" (garlic, vitamin C, echinachea, IIRC) even if you don't have symptoms of mastitis- you might have a sub-clinical infection. I went through that when my DS was a little over a year old, and it cleared up when I started treating it like it was mastitis.
Also, make sure your bras fit properly (if you wear bras.) Too-tight bras can contribute to plugged ducts.