I don't generally recommend the peppermint tea any more but as long as you've not seen any changes in your cycle, carry on.

Yes, you need to continue the diet (not just skipping breakfast, but the whole diet) until you get a BFP. We see VERY dramatic differences in people who only did diet 2-4 weeks as opposed to 6+ (and of course 12+ is best) and given the poor results for 2-4 weeks of diet, it does not make any sense to go off diet 2 weeks every month!

Please continue exercise till BFP.