Weather doesn't effect freeview frequencies as much as lets say sat freqs..
More than likely the coax has popped out of the connectors, the antenna/coa-ax join wasn't sealed up and has got waterlogged, or a strong wind/bird has knocked the antenna slightly out of alignment..
Also before you do anything check with a neighbour as it could be that work is being done at the transmitter...
But I will say that the antenna you bought is designed for minimal visual impact in a good signal area, or for example caravanners.. best to get a decent antenna something like:-
http://www.amazon.co.uk/SLx-27884D-E...5168053&sr=1-6