I don't think it opens till November but there is supposed to be a CVS drugstore in the new Marriott Springhill Suites Convention Center at the corner of Katella/Harbor. Not sure if it's going to be a full sized CVS or what. If you're looking for groceries, they usually have a decent selection of chips/crackers/beverages/canned goods/cereals and also a small frozen food section and dairy case, some also have bakery products and breads.