Having my periods, but i still get the pregnancy signs

I have been experiencing all sighns of pregnancy,nausea,fatigue,sore nipples and so on last month on the third i had my period for three days,thn last week or the week before i spoted . This month im having my periods but i still get the pregnancy signs,im constantly feeling dizzy,wanting to haul,and my belly is growing.people that knows me say i look pregnant. Could i be pregnant and not know it.