Searching for strings is broken. A string like "me too" returns posts that contain "me", "too", and "me too".
This is intentional, the default search operator for Stack Exchange sites is
AND). Also, the default search result screen is relevance, so ones matching more terms will be presented up top, with additional posts you may be interested in listed below.
Additionally, by default we roll up to showing questions, so the match for "me too" (if you are using quotes) may be in an answer.
For more info, see the search help/options.
This has been the case for a while (at least a few weeks). In a pinch, you can add a
body: qualifier and it seems to work. Something like