I feel so very bad for you in the state that you are. I have been through so many low depressive times of this illness too. Believe me I have been there when I wanted to end it all too. It got to the point that was all I was thinking and planning about day after day.
You really need to call your doctor and let them know EXACTLY how you're feeling. Let your doctor make the next decision for you. You may need to go into the hospital until you are in a more stable condition or perhaps he may make a med change for you.
I don't like the idea of you being left alone during this time. I know it really sucks at times and ending it all sounds the easy and most sensible way out to you.
Please get yourself some help. I for one know that brighter days will come back and one day you will be at your normal self again. I just came out of a 2 year depression cycle and believe me many times I "Thought" I would never be normal again.
I am here today, feeling Great and can't believe how far I have come. It is a battle but it is worth the fight. A fight you don't have to battle alone. You have your Pdoc and maybe you should find a therapist. Those two combinations have helped me tremendously throughout the years! Your husband sounds very supportive. Luckily mine was too. Please reach out another time and get the help/support you need at this difficult time for you.
I hope nothing but the best for you. Please keep in contact with all of us here. We want to hear how you are coping.