No AF and negative test what do I do?

Hey everyone! I'm 5 days late according to glow I'm abit worried as my last period I came a day early! 🙈 I have been exercising alot at my work but last period I was excersing so don't understand why I unless it's a thyroid issue? but I been having period like cramps, sore boobs, tired, mood swings and feeling lightheaded all the symptoms of pms but no period and took a test this morning and negative but I did test on my second morning wee as didn't go bed till late haha what do I do please 😔