Swapping one career for another can be incredibly stressful. That is the best-case scenario. Sometimes, the mental fatigue and anxiety experienced when considering moving to another area of employment can lead to physical and mental health problems. The last thing you should be doing is adding to your stress.
This means you should have your finances in order before you decide to start upon an entirely new career path.
You should already have a budget that you follow religiously. If you don't, start one now. Write down every single outgoing expense and every bit of income. Look for ways to streamline your outgoings, and improve your income. If there is no way you can earn more money, just cut back on your expenses. This will account for automatic savings, which can present a nice cushion if your career change doesn't offer the immediate financial rewards you're looking for.
When switching careers, it is common for you to have to start out earning less money than you are now. This is not always the case, but it is much of the time. Having a year's worth of living expenses tucked away gives you the peace of mind to dedicate your mental energy to succeed in your new career. You won't be worrying at the end of the month how you are going to pay your bills.
You may also decide to take on a part-time job to make some extra money.
If you do this, try to get employment that will teach you skills and abilities useful in your new career. A part-time job makes you money two different ways. Obviously, you get paid for your labor. Also, if you are spending a few evenings each week working, those are not nights you are out and about spending money.
You may have an opportunity to move into a smaller home or apartment. If this makes sense for you, by all means, do it. Cutting down on your monthly rent or mortgage is a fast way to free up some substantial money. Have a garage sale, or sell some of your possessions online. If you like gardening, start a backyard garden and sell your produce at a local farmers' market.
If you're serious about changing careers, you don't need a lack of money to make the situation harder than it already will be. Ask yourself some hard questions about the money you spend, and see if you can generate any new income. In just 6 and 12 months you could set aside enough money to keep your mental focus on your new career, instead of worrying about your finances.