Girls I’m in need of some advise!!

I’m currently 13 days late for my period, I stopped taking my pill on the 5th January and I normally have a period within 2/3 days of stopping it (I’m on the pill which you take for 3 weeks then have a break for 1)

Due to not coming on I haven’t taken the pill since and me and my partner have sex regularly well daily maybe twice a day.

I took a pregnancy test on the 16th and it was negative I then took one 2 days later and it was still negative!

I’m now stuck with what to do... I’ve been feeling very tired I slept the whole day yesterday and I never do that! now today I’m feeling a bit nauseous and have a headache! I know this can also be pre period symptoms but I just need some advice please!

TA!