some advise please

okay so my period is now 3 days late which isn't really normal its usually regular. i been having nauseous and lower back pains i been more tired then usual and i don't feel hungry but when i do eat i eat allot more then i usually do my boobs don't hurt but they look different like darker i been getting headaches on and off also but i have had no implantation bleeding or spotting at all? when i took a test yesterday it was negative but i took it at work in the middle of the day. are these signs of being pregnant? when should i test again? anyome know whats uo? thank u guys