due date change

today i had a brief moment of complete shock and excitement. then logic hit me and that elation died. here's the story.

at the doctor's. 15 weeks today and excited to hear the heart beat. all was well. we heard it, it was pretty cool and very strong. woot woot!! then the doctor checked my dates again to see what my due date was going to be (this happens every time i have gone to the doctor. i know how far along i am and i know my dates so i don't need him to do this every time....is this what they always do?). he told me that i am 18 weeks and 2 days and that my due date is april 18th. WHAT??? YAY!!!! i am almost half way done! this is SO AWESOME!! then logic sinks in. last time my due date was may 11th. how did i skip 3 weeks? i had an ultrasound on oct. 13th and i was 10 weeks....that was 5 weeks ago. i am so confused. if i was 10 weeks last month how am i over 8 weeks further along? "8 weeks is just short of 2 months. it hasn't been 2 months!" steve and i spent a good 5-10 minutes explaining our case and how, sadly, i can't be that far along. the doctor remeasured my fundus and said that it's hard to measure on me (stupid tilted uterus!) so he can't totally tell. again, i went into my logic. he showed me the wheel thingy they use for dates and it said 18 weeks and 2 days. but i still don't care. i know i am right. after more talking he is convinced. he realized he was doing the wheel thing wrong and we had a good laugh (he was putting it as 13 weeks on oct. 10th, rather than 10 weeks on oct. 13th). SHOOT!! i almost wanted to just go along with it cause then i could tell everyone that i am 18 weeks and not 15....but really that wouldn't get me anywhere. i wouldn't have the baby earlier and the next ultrasound would show that he was wrong. oh well. it was exciting for a few seconds. he did change my due date....from may 11th to may 12th. dang. further away....but 12 is my fav number so whatever!