you have irregular and delayed periods...
you have also mentioned that you are thinnly built..
but still you may be having PCOD
, which causes irregular periods
and difficulty in conception..
see your gynaecologist for the examination and investigations.. you have sore nipple/mastalgia, which could be due to hyperprolactinemia
the sneezing/coughing is a different issue, probably you have allergic rhinitis
, see your physician for the diagnosis and treatment..