Just got back from my W5R3. It was a bit challenging but do-able. The last 2-3 mins was the toughest. But I did it ! As one of the posts said, thinking of it in 5min chunks works perfectly.
I feel this is the turning point to go longer without breaks.
So, I thought (trying to get some air by the end ) I heard Laura suggest repeating W5 if we feel like before going on to W6.
Again, thank you all for the great encouragement.