Why do I feel awful?

I’m almost 2 weeks PP without 3rd little boy and we decided before he got here that he was the last one and we are done. I already have surgery scheduled to get my tubes out and he keeps talking about getting a vasectomy which is fine, that’s his choice. Problem being I can’t wrap my head around our newest addition being our last. I knew it was going to happen at some point but I’m having a hard time accepting it. I love our littles so much and I know that financially 3 is all we can realistically handle. I cried nonstop when I got the confirmation from my insurance company saying the procedure was approved. How did you ladies get over the sinking feeling of knowing you were done having babies but still feeling depressed every time it came up? Did you celebrate that feeling or just completely ignore it? I’m a little lost at this point.