Nope, you clearly want to fly and so you should continue. Of course you will be despondent, but the sense of achievement you will feel when you get your license will be all the greater.
Air Law is the most unpleasant exam I've ever done (and I've done a load). It's just a grinding memory test. The other topics are much more interesting, so I shouldn't worry about it.
I would suggest revising in absolute quiet (that works well for me) in short chunks or 30-40 mins tops. Pick up on the individual topics for each session. For example, aerodromes, privileges, classes of airspace, safety and that damned Chicago convention stuff. Examination aids such as the PPL confuser are helpful if you can get one. They appear on eBay from time to time.