SHEEPSHEAD BAY - New buildings are popping up like mushrooms in Sheepshead Bay, but existing residents say extra crowds, are diminishing the quality of life in the area.Emmons Avenue has been hit hard by huge condominium units that block water views, residents complain. Community leaders say the new housing is drawing more people to a neighborhood already struggling with traffic congestion, parking problems and sanitation woes.Though no single developer is responsible for the new housing, Community Board 15 has been inundated with complaints. Local businesses say the increase in traffic hasn?t benefited them because customers are being driven away by a lack of parking. Developers did not respond to phone calls seeking comment.