Hey mama, ang chills and feeling cold sa first trimester ay pretty common dahil sa hormonal changes, pero importante pa rin na i-monitor mo especially kung may fever ka or pakiramdam kang may sakit talaga, better safe than sorry, kaya siguro best pala mag-check with your OB lang para sure! A few of my mum friends experienced the same during early pregnancy pero iba-iba ang reason, so mas maganda talaga na marinig niya ano ang happening sa body mo. Take care!