There are many synonyms that you can use instead of the phrase "was proud of". Some examples include "felt satisfied", "experienced admiration", "was pleased with", "felt a sense of accomplishment", "was elated by", "felt triumphant", "took delight in", "felt a sense of pride", "was gratified by", and "felt contented". Each of these phrases can help you to express a similar sentiment as "was proud of", but with slightly different connotations or shades of meaning. Experiment with different synonyms to find the best fit for the particular context in which you're writing or speaking.