I am typing this at 3:45am and honestly feel like I am losing my mind

About 3 weeks ago, falling asleep started becoming more and more difficult for me (since having DS I could usually fall asleep in seconds so I found this quite surprising). I am now at the stage where I am only managing to fall asleep between 2am and 4am. Night after night.

I have an 18 month old whom I need to care for during the day and it is just getting harder and harder to function properly on such little sleep. Bubs is due in 7.5 weeks and I honestly don't know how I will cope doing this for another 2 months

I have tried napping while DS has his afternoon sleep (I seem to be able to fall asleep then). I have also tried just pushing through the day without any sleep in the hope that I will be exhausted and will sleep that night. This doesn't work either. Night times are becoming such an anxious time for me, which is clearly not helping things and just resulting in a vicious cycle.

Has this happened to anyone else? What did you do? Did you seek medical intervention? Any suggestions you may have (besides the usual warm milk, bath, lavender, staying up until you are tired etc. suggestions - none of which are working for me), would be greatly appreciated.

Thanks