I am 17 weeks with my second baby,and have had thrush early on in this pregnancy & towards the middle with the last.
I used a clomatrizole pessary both times but did not use the applicator,it was in a tablet form & I just pushed it in with my finger(not too far up!!),make sure you put it in just before you go to bed,and you should get a little relief by morning,but give it a good couple of days to cure it completely.
Thrush makes you utterly miserable,do'nt suffer,get it sorted.Good Luck!!