Is admitting to self-harm worth the cost of losing everything I have? My job, my income, my family? I'll get fired if my work find out and I couldn't live like that.

In my experience, it's worth telling someone you trust completely. Whether they offer you help or are just simply someone to confide in, it is so much easier to help yourself and truly get better once at least one other person knows what you're going through and what you are trying to do. If you dont have someone you can trust in real life, confide in a listener here and/or join community discussions. This could never affect your job and gives you at least a small support system to help you on the road to recovery. It's an extremely difficult thing to do but it is so very worth it.