Hi Virginia! Consider this article; http://www.myenglishpages.com/site_php_files/grammar-lesson-many-much.php I hope it's helpful. :)

'Too much' is used for uncountable nouns, whereas 'too many' is used for countable nouns. 'A lot of' can be use for either. eg. Too much milk, too many footballs, a lot of milk and a lot of footballs. Countable and uncountable nouns Nouns can be either countable or uncountable. Countable nouns (or count nouns) are those that refer to something that can be counted. They have both singular and plural forms (e.g. cat/cats; woman/women; country/countries). In the singular, they can be preceded by a or an. Most nouns come into this category. A smaller number of nouns do not typically refer to things that can be counted and so they do not regularly have a plural form: these are known as uncountable nouns (or mass nouns). Examples include: rain, flour, earth, wine, or wood. Uncountable nouns can't be preceded by a or an. Many abstract nouns are typically uncountable, e.g. happiness, truth, darkness, humour.