Late for period.

Hey there I recently finished low risk chemotherapy and got all clear in January after a full molar pregnancy, my period has been every 27 days my last period was the 9th of March then I had a little spotting on the 19th for 3 days but was the littlest of blood when I only wiped, I got a pregnancy test 8 days ago and it was negative so might test tomorrow as I'm 5 days late now, I have been having headaches feeling sick going pee every 40 mins had diarrhoea but never usually do also been tired recently just wondered if anyone had this symptoms and were pregnant, I wasn't trying we use condoms but possible it could of split, I'm going to test tomorrow as having no signs of a period xx