I would advice you to go for a ultrasonography
of pelvis to know whether she is pregnant or not.
The symptoms described are related to pregnancy
but can't be sure untll the sonography is done.
The brownish spotting might be due to implantation
, but cannot be surely said till her cycles are regular and I know when was her last menses.
Either wait till she misses her periods and get a HPT or go for a scan and meet your doctor with the reports.
Take care,all the best
Dr. Rishma lakhani