Congrats on the pregnancy, I don't think you should take anything to keep awake, your body is going through amazing changes that use a lot of energy, when you feel tired its a good idea to rest as much as you can when you can, I know it's hard at work or when you not telling anyone yet you pregnant but generally our body lets us know what we need when we need it.
When I was in my first trimester I also struggled with exhaustion, to the point I had some deadly disease, lol then found out I was pregnant,

but I started eating more healthy (fruits & veg mostly) and it helped, I also found that as we age the follow-up pregnancies our body has aged and they don't perform as well as the first pregnancy, but I also used in my first pregnancy and now in the second a thing called, Herbal force Blackberry Elixir, it's natural and safe during pregnancy and while breastfeeding, you can take as an extra boost, it really helped me, I just diluted one teaspoon in cold milk as it's very sweet for me and it did work for me.
Good luck with your pregnancy, it will get better soon!!! But it comes back in the last trimester, I can't keep my eyes open anymore

again