It was a doubly painful day for Auburn. Mississippi State struck for three runs in the the seventh and another in the eighth for a 4-3 walk-off win over the Tigers and a sweep of a doubleheader Sunday afternoon at Dudy Noble Field. The Bulldogs won game one of the doubleheader 3-1 to complete the three-game sweep. AU falls to 19-20 overall and 2-16 in the SEC with an eighth consecutive conference loss. “So far it’s just been one to forget in league play,” AU coach Butch Thompson told the Auburn Network. “We were in position up 3-1 in that…