Hi Emma Jayne
I think every clinic is different - some people on here I know have been told to wait three months. My clinic says you should have the period that resulted from the failed cycle and then one more 'real' one, then it's fine to go again after day 21. I did this - so in essence it was barely two months between my first cycle ending and starting my next, however I think I went again a bit too quickly. I breezed through my first cycle with very few side effects and during this one I felt absolutely rotten especially when downregging. If this one doesn't work (quite likely as I'm threatening m/c as I speak) I think I'm going to leave it a few months to give my body - and my poor DP - a rest.
I started first ICSI cycle in May of this year which resulted in pregnancy -> m/c. My consultant advised that I have a natural cycle before trying again. I began again in Sept (FET) and am now coming to the end of my 2ww.
I went into it again very positively even a little excited but have also found it far more emotional this time around for some reason but am trying to stay positive.
Good luck whatever you decide, I think that if your Dr gives you the go ahead and you feel positive and ready to go for it, why wait?
Hope this is of some help, sending lots of love & luck to you,