Does any one else feel how i do....?

why do i feel the way i do. I have been on anti-depressants for 20 years and have only just been offered help with councelling. well cognitive therapy to help u deal with your worst fears. I have the most awful fear that something will happen to one of my kids, especially the teenager. It overtakes my thoughts, and makes me feel so low, i get up and think not another day, what is the purpose of living. Although i struggle on, and no one really knows how bad i feel, its so hard. Do most people walk around with a mask on, or are there genuinally happy people out there, who live life for what it is. I took myself off the anti-depressants to try and see if i could cope without them, but no i have been very low and tearful, without them. I seem to live my life on what ifs. what if this happens how do i cope etc etc.. I know its mad, but i just cannot stop these thoughts...