Just making sure I'm doing this right: Should I have a full period after 'in my head', or not? Whaddya think? ~ J. J.
Yes. That isn't a dialogue tag (you can't sputter a sentence intelligibly), so it should be treated as a beat (a separate sentence) and punctuated accordingly. For that reason, drop the final comma at the end of the first dialogue fragment as well. And don't begin the second fragment with an ellipsis. Speech can trail off, but it can't trail in.
there should be no space before 'Is' after the ellipsis... and it requires a fourth dot for a period, since the first two words are a trailed-off sentence... same goes for after 'this'... see why here: http://fandom-grammar.livejournal.com/2828.html [scroll down to 'Ellipses can also be used to indicate speech that trails off from one sentence, leading into a new sentence.'] plus, a comma would go after 'sputtered'... sense-wise, i'd say 'words and thoughts' would be redundant...
I'd take it a step further and suggest making it two complete sentences by eliminating the the phrase "as words and." After, of course, making sure that you're using the ellipsis in its correct form.