hi, I'm also 19weeks pregnant and have to put up with oily cooking smell from my neighbor daily and hourly starting from 8am to 10pm. I will usually suan them of the cooking and the oily smell will immediately disappear and be replaced with their spraying of baygon and air freshener 5 seconds later, which is air polluting and toxic. I've complained to HDB multiple times but they ignore my complaints.
I have a smoking neighbour - had you tried closing the windows and buying an air purifier? Xiaomi is quite powerful and more affordable. Do be careful what oils and sprays you use, in case they might not be good for pregnant mummies.
Chew on a piece of gum or suck on a hard candy. It will help take your attention away from odors. Peppermint candies is the best