gone?

I haven't seen the catbirds in a few days- I distinctly miss their presence hopping along the fence or flitting in the nearby trees. I am feeling guilty that maybe I disturbed their nesting site- they seemed fine with my nearness working in the garden, but probably when I peered into the bush it was too much. After realizing they were gone, I went ahead and trimmed the top of that euonymus, where new growth was sticking up awkwardly. No birds flew out in alarm. So I peered into the nest from above- three blue eggs. No parent. It's just as likely they met with some accident, but still, I feel bad.