Eh, normal je tu at 18-19 weeks, hormones memang buat kita rasa mcm oven! A few of my mum friends complained pasal yang sama, especially kalau pregnancy tu during warm months. Try wearing loose cotton clothes, minum banyak air, dan cooling pads boleh juga, and jangan lah stress about it, sebab baby pun fine, just mama yang kepanasan. Hang in there, third trimester baru teruk betul!