I watched for love-cars. Lights turned down, (line 27)
Sad and lonely! Our speaker drives up the hill looking for signs of love and activity in his town, because he is all by himself.
'Love, O careless Love . . . .' I hear my ill-spirit sob in each blood cell, (lines 32-33)
Hearing the love song on another's car radio reminds our speaker of how loveless and lonely he is.
nobody's here – (line 36)
This is a literal example of his isolation. Nobody's around.