To make a career in law, doing a law or non-law degree is irrelevant. What all current trainee solicitors and barristers have in common is that they have fantastic backgrounds, they won loads of awards and commendations at university and strongly demonstrated their interest to work in the legal profession.
You can do a law degree or a history degree or an English degree or a degree in Sports medicine, but if you don't have a strong 2:1/1st, the chances of making a legal career are slim to none (at a good City firm/set that is).
Also, law is challenging, but it varies from person to person. Taking one person's opinion on it is tantamount to idiocy.