Use that link to help. I just stick to saying how many weeks I am or else it's just to confusing with 40 weeks being 9 months.
http://www.baby2see.com/pregnancylength.html
Because there's about 4.3 weeks a month you actually hit your second trimester (so 6 months) at 27 weeks. Right now you are 5 months and a week.
You are 5 months pregnant.
When you hit 24 weeks, you will be 6 months along.
I hope this helps (: