help!!!!!!

How does a pregnant woman not know how many months pregnant she is?!

I am 22 weeks pregnant. 22 out of 40 weeks....how many months? I have no idea! Every website contradicts itself.
Website 1:
1st Month = Wks 1-4
2nd Month = Wks 5-8
3rd Month = Wks 9-13
4th Month = Wks 14-17
5th Month = Wks 18-21
6th Month = Wks 22-26
7th Month = Wks 27-30
8th Month = Wks 31-35
9th Month = Wks 36-40

Website 2:
0 Month = Wks 0-4
1st Month = Wks 6-8
2nd Month = Wks9-12
3rd Month = Wks 13- 17
4th Month = Wks 18-21
5th Month = Wks 22-25
6th Month = Wks 26-30
7th Month = Wks 31-34
8th Month = Wks 35-38
9th Month = Wks 39-42

ahhh!! I am either just turning 5 months pregnant or 6 months pregnant! How can the counts be so different!? While this pregnancy is going quickly...I really would rather call myself 6 months and not be just starting my 5th.

The solution? I am going to the doctor tomorrow. That. is. right. I am going to interrupt the nurses at my OB's office and ask them how many stinking months pregnant I am and then I may cry on the phone if they don't tell me what I want to hear.

oh, and word to the wise, I was never 0 MONTHS PREGNANT. I was sore and nauseous from week 3.5...that's why I took a test and that week counts as something. 0 months pregant my foot.