Could she be pregnant?

So my 19 year old niece who is a bit shy of asking anyone personal questions asked me one about being pregnant. She told me that her and her boyfriend had sex on April 29th and that her period came right after that and ended on the 9th. (she has a regular 28 day cycle btw) Then starting on the 20th she had some spotting that lasted for 3 days and then 2 days of a more period like bleed. Shes afraid to take a test for the fear of being pregnant but thinks deep down she could be. Not sure if shes just stressing out but shes been complaining of feeling like shes coming down with a cold and is now constipated ( her gallbladder was removed and has had no problem going if u get my drift) what is your opinion on what is going on? plz no rude comments