Can I take melatonin while pregnant to help me fall asleep at night?

Hello, I found out I was pregnant two weeks ago. According to my calculations, I am about 6-7 weeks pregnant. I have been taking melatonin for a few years to help me fall asleep at night (I have been suffering from insomnia for a very long time). Since I found out I was pregnant, I stopped taking it. However, I now go several nights without sleeping, otherwise I only sleep 2-3 hours a night. I have tried taking a gravol tablet before bed, as it can cause drowsiness, but without success. All this fatigue has of course an impact on my daily life.