Is bread countable

The noun bread is a mass (uncountable) noun. Individual units of bread are expressed as a loaf of bread, loaves of bread, a slice of bread, slices of bread, pieces of bread, etc.

You would not say "There is a bread on the table.", you would say, "There is a piece of bread on the table." or "There is some bread on the table."

The plural forms for a mass noun are reserved 'types of' or 'kinds of'; for example:

If you say, "There are five breads on the table." it means five kinds of bread such as Italian, rye, French, corn, etc.; or "He bought breads." would mean that he bought the sandwich bread, the hot dog rolls, and the hamburger buns, or whatever kind of breads were expected or needed.