5'6" is short but not freakish. Also, there's a world of difference between 135 pounds and 115 pounds. I was 5'8" and weighed 135lbs for years. I had no trouble buying off the rack suits.
If I were you, I'd pick up four BB Fitz suits is size 36S, two pair of AE shoes, and round out your closet with dress shirts, socks, belts, and ties. That would be very very easy to do for less than $5,000.