Blue Kingfisher, I'm really sorry to hear that, it must be so disappointing.
First of all, yes, you can use the lozenges cyclically but you would need to take about 50mg every day for a couple of weeks and I would suggest you do this on a longish cycle.
Before trying that, I would suggest you continue with the Oestrogel and stop the progesterone for a few weeks to see if you feel any better. If you feel a massive improvement, then the progesterone must be the culprit but if not, it could be that Oestrogel doesn't agree with you or the dose needs tweaking.
I hope that helps.