I think it would sound nice to say, “I think I've found the perfect word to sum up my whole life.” or, “I think I’ve found the perfect word to sum up my daily life.” You can use the words, “my whole day”, “my whole life”, and “my daily life” lumped together, but it sounds strange to say, “my whole day life”, because “day” is a noun and “life” is also a noun.... In English, it’s not usually very natural to put two nouns next to each other. So a good rule of thumb is, if you want to describe your life, and you need to add extra details to the word “life”, add an adjective first. You could say, for example, “my daily (adjective) life (noun)”, “my boring (adjective) life (noun)”. You can use “my whole life” and it sounds very natural, but putting “my whole daily life” would also sound weird. ... Even though the sentence is a little ungrammatical, it’s very understandable. Good job.

Neither sentence is clear. Maybe these would be helpful; I think I have found a good word to summarize my whole day. I think I have found a perfect word to describe my day. I think I have found a way to summarize a typical day in my life.

Thanks, guys.

have found the**

Gee, I don't think either is very good. Perhaps: "I think I've found the single word that sums up my entire life."