Oo mommy, normal yan sa first trimester kasi ang hormones mo ay sobrang taas at bumabilis ang metabolism mo, a few of us dito sa group experienced the same thing, parang mahigpit na init lang talaga every night. But since you're hitting 38-39 consistently, mas safe if you check with your OB lang to be sure walang infection o iba, kasi minsan mahirap i-distinguish kung pregnancy-related lang or may ibang nangyayari, lalo na kung ganyan ka-regular ang fever.