Assume a 1.5 oz bag with 6 different colors, 9 m&m of each color. Total of 54 pieces in bag. Probability of drawing seven consecutive of the same color is:
P = (9/54 * 8/53 * 7/52 * 6/51 * 5/50 * 4/49 * 3/48), which is roughly 1 in 5 million.
This is the probability of drawing the seven immediately upon opening the bag. If you ate some non-orange m&m's before pulling your seven, then the probability would increase.