The phrase "hadst signs of" is an archaic way of saying "had signs of." The word "hadst" is an inflected form of the verb "have" in the past tense second person singular form. The spelling "hadst" is pronounced /hædst/ in IPA, with the "h" sound being followed by the "æ" sound as in "cat." The "d" sound is followed by the "s" sound, and the final "t" sound is pronounced softly. This old-fashioned way of spelling and pronunciation can be found in literature from centuries ago.