Covid 19 test

So as from Sat I wasn't feeling well at all, yesterday decided to see my Gp and aslo she requested a covid 19 swab test oh well momentum responded that I haven't been with an infected person.. My question: I travel by public transport to and from work, so the likelihood to have been in close proximity to an infected person could habe happened anytime. So how would I know? website contradicts this letter because on the website they say if you are high risk and suspect you might habe been exposed, you must consult a doctor which I have done. Momemtum reference ***