I hate to say it but if you are that tired already chances are you will be more tired as you get more advanced so working full time to due date may not be possible. The tiredness didn't hit me until about 35 weeks. Carrying the extra weight does tire you out.

I worked til 37 weeks and it was about one week too long. I gave birth 1 week & 4 days before my due date. The last week at work I had to drag myself around. I was so tired and had swollen ankles and feet. It was such a relief to get off my feet and sit at home. You may need to reconsider your plans to work so late. Very few women manage to work right up til their due date. Most of the women in my BB buddy group finished up before me and they were all younger than me.

As for the cramps - I only had two throughout my pregnancy and attribute it to the use of Tums for my indigestion. They contain calcium which is what some doctors will tell you to take if you are having problems with cramps.