GDP is a mere indicator based on the total cash sum of all transactions in an economy. Increased consumption of goods and services doesn't necessarily equate a healthier economy.
The former communist economy of Bulgaria was a very different beast altogether. Services were practically non-existent, or entirely in the gray sector where individuals were repairing cars or giving music lessons to children for cash and mutual favours. The structure of society eliminated the need for whole classes of services which are in the private sector today - think private healthcare, travel agencies, consulting agencies, analytic agencies, etc.
The current IT industry in Bulgaria is not a game-changer for the whole country. It consists mainly of outsourcing companies concentrated in Sofia, exploiting the relatively cheap labour there. Few local companies develop their own product and accumulate their capital locally.