That is basically what I did, except instead of pessaries I was swallowing 8 tablets a day. I continued the injections until my 13th week and at that stage began weaning off the progesterone tablets then too - I think it was about 10 days of cutting down the dose, so basically 15 odd weeks on I was drug free. The result of the first BFP I followed this regime with is my DD3 who hit 20 months today. I hope you have similar luck.