I would say... 1) I feel a little sheepish GETTING so fooled by a silly little book that she wrote. OR I feel a little sheepish GETTING fooled so much by a silly little book that she wrote. (I think that SO or SO MUCH as you wrote them are both acceptable. SO in the first sentence is more common in spoken English and is more informal, often used by younger people. It is used as an intensifier, in this case to intensify how much you were fooled, like saying REALLY fooled.) 2) I think either are correct. See explanation above. 3) I think "fooled as much as" or "as fooled as" are both correct and equally acceptable; however, I would say "as he was" in both cases rather than "as him"