I suggest you plan a break even point unless you have financial backing for your handbag business. Leavng a job, with known income, for the uncertainity of a full time business can be so stressful that the pressure to produce just overwhelms you. I would look for a better paying part time job and/or get a better paying full time job so you can sock away some money for your business. Look for ways to pssively sell your handbags such as e-commerce so you can build a fund.
No, do not leave a full time position until you have some money behind you.