I'm fine but the heat is sweltering and I can't really sleep well.
I'm good but it's so hot and uncomfortable even at night that I can't get a good sleep.
1) I'm fine but the heat is sweltering and I can't really sleep well.
「元気ですが、暑さがうだるほどでなかなか眠れません。」
sweltering で「うだるほど」
2) I'm good but it's so hot and uncomfortable even at night that I can't get a good sleep.
「元気ですが、夜もとても暑苦しくてなかなか眠れません。」
hot and uncomfortable で「暑苦しい」と言えます。
ご参考になれば幸いです！
日本 
