confused....

Hey ladies , so I'm a little bit confused . I had two period back to back in the same month , I usually start the last day if the month and then continue to the next month . I've yet to start , earlier today my daughter and I went to go return a pair of shoes for a different pair before we left to get into the truck I started to feel nauseous thought i was hungry I had a big lunch today and I was pretty full so I ate a little snack to see if that was it and I'm still feeling really nauseous. my husband said my boobs look a little bit fuller then they usually do , they are sore . Should I take a test or could it be my period ?