Feeling bad after abortion

8 months ago, I got pregnant. I already have 2 daughters (7 and 9 years old) and I am 35 years old. I choose to stop this pregnancy for many reasons (they were probably good at this time) but now, I feel terrible about my decision. I am always questioning if it was a good decision or not. I know it’s the past and I can do nothing about it but it obsess me. I think about it all the time.
Since then, I am always debating with myself if I want a 3rd child or not. Sometimes I want one really hard and sometimes I don’t.
I would love to hear how I could get through this and how I could be able to move forward and stop wondering about having or not a 3rd child.