I smiled if worried about discontentment in career: is – that it? (7,6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

not sure about definition: 'that it?' could be a question on one's mind in a midlife crisis ('is this all there is to [my] life?') …or, it could refer back to the worries and discontentment earlier in the surface anagram/"worried" of (I smiled if)*; around C-aree-R ('discontented': contents removed) plus IS (from surface)