Some essential oils solutions do work, it’s just a question of finding the right one.
For my dogs when we go on walks in the woods, we use this https://www.amazon.com/Vets-Best-Treatment-Repellent-Certified/dp/B003QS6JL2?th=1 It makes you smell like cloves (my DH says they smell like an Easter ham), but it works super well. It is especially effective if you really douse their feet in addition to a general all over spray. Of course, it doesn’t say anything about use on humans so maybe not so helpful. Although I have occasionally sprayed it on myself.
Also consider having some dedicated clothes that you can treat with a repellant like https://www.rei.com/product/768970/sawyer-permethrin-pump-spray-24-oz These work quite well. I would just change as soon as you come back inside considering you’re pregnant. I wore clothes sprayed with this stuff all day everyday for two weeks while on safari with no ill effects.
Ticks are the worst. We also have a lot of woods around the farm and I’m considering using this https://mosquitobarrier.com/ticks.html this year. I had to treat one horse for a tick illness last year and the cost of that more than covers the cost of the garlic spray. Also, I read somewhere that this is what Disney does for bug control and I have to say, Disney is strangely bug free . . .