My first date with 17P injection

Today, at 17w6d, I had my first injection of 17P (it has a long scientific name, but it's a progesterone compound in Castor oil).  Ow!  It was a relatively painful injection, mostly because it is thick and takes a while to fully inject in the muscle tissue.  Of course, the burning subsided not too long after the injection, so imagine my surprise as about 30 minutes later, while making the kids dinner, it started majorly hurting.  In fact, I reheated the heating pad and strapped it on while in the kitchen.  Yowza!  And I still have 19 more injections to go until I'm done! :oO
My mid-back has been pretty sore lately and I'm definitely getting the the first level of discomfort, not to be confused with the all-encompassing, massive discomfort to come as I run out of room and end up as large as a house.
Tomorrow I will be 18 weeks, meaning it's that magical time at my next ultrasound (Friday!) that I find out whether I am baking a little boy or a little girl.  I also get to find out if my body is working with or against me and if I need further intervention to keep baking the baby to full term.  I'm oddly very calm about finding out the gender.
Perhaps it is having one of each already that makes it seem slightly anti-climactic, but the "planning" side of me needs to know.  We got rid of almost all of our baby stuff - we have a crib, the matching changing table and the double jogging stroller, and that is it.  The smallest clothes I think are 18-24 mos in boys and 3T in girls.  Um, yeah...not super prepared here.  It's funny that after 4 years, it feels slightly like starting over again.  It will be so weird to have tiny clothes, tiny diapers, and all the wonderful things that will fill up our house yet again.
So I suppose I'll be back to post this weekend and give the gender verdict.  Until then, I'll be hanging with my new BFF - my heat pad. :)