What Causes Regular Periods With Positive For Pregnancy Test?

my question is i had all pregnancy tests show up postive and they got darker right before i started my period and well after i had my period i didnt worry about being pregnant but my gut told me to take another since ive been dizzy and light headed latly and i have gotton blue veins on my breasts leading up to my nipples and well i took an ept and it showed up postive again but i didnt think you could have your period while pregnant so im wondering whats wrong could i be pregnant?