Re: Feeling ashamed about this...
That is very similar to what I would experience when nursing my daughter at night when I was pregnant. It was semi-sexual and npleasant. The best way I could describe it would be to say, it's exactly what it would feel like if a man were trying to suck on my breasts when I didn't want him to. I would have the instinctive urge to knock my daughter away (I didn't, but I wanted to).
It's definitely hormonal, beyond your control, and there is nothing wrong with you so try to stop worrying about that. Let's try to come up with some things you can do to get past it or overcome it. I like mommal's ideas about breathing and visualization. Also, try to think about what is going on when it does happen. For me it only happened at night when I was half-asleep. Is there a time of day when it seems to happen more frequently? Is it when baby is comfort nursing vs actively eating? Think about things like that and maybe you can find some clues about what you can do to change/avoid it.
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”