You are correct. Unfortunately, you were one of the unfortunate that had just under the required activity to bump up to next rank prior to merit. You do indeed need another149 merits.
WOW it's going to be a really huge chalange to me to atcheve that, even if I take +1 merit a day it is very long road.
I guess everyone who will quote me will say to concentrate on high quality posts, but as I see even such posts do not get any merit sometimes, but simple ones, like this
Wow how i should get that much merit 
100 for Full Member
do. 100 for Full Member