To heal abandonment issues and fully recover, it helps if you're aware of your initial reactions to the first experiences, so the "lies" may be revealed. Believing that you are not good enough often begins at the time of these first experiences and were strengthened with each new one.
In other words, step one is learning to tune in, to have the awareness of the false, adopted beliefs that first popped into your mind when these life events happened. You don't have to remember each and every situation that reinforced these false beliefs, but remembering some of them can be very useful. I suggest using an icky-colored pen for a "Lie List" and write them down.
The second step is to congratulate yourself for the awareness, by saying, "Good for me, I'm helping myself heal." Once these old lies are exposed for what they are, there's room to replace them with truths. This is the third and final step for this exercise. Make a new list using a pen with a beautiful color for you're "Truth List." Here's where you counteract the lies with the statements that you rationally know are true, and you will realize that you deserve love.