I remember feeling exactly how you feel now and just continually going through things in my head - I couldn't get over the feeling of feeling 'empty', yet it seemed odd as I made a choice to terminate - so why was I feeling empty? One of my friends on Mumsnet who had also gone through an abortion said 'time will help' and I remember thinking 'I'm not sure it will'.... You might feel the same, that no matter how much time passes, it won't help - I think it will, however I don't think you'd ever forget - I've not forgotten, but it does get easier from a day to day perspetctive.
As for thinking of trying to get pregnant again - No, I couldn't go through the depression again. I got to the point of writing my goodbye letters and planning how I was going to take my own life and I believe if I was to try pregnancy again - the same thing would happen, even if I was heavily medicated.
Different people react to pregnancy in different ways - part of my own battle is hormones, but another part is sheer overwhelming panic when I think I'm not in 'control' and having witnessed my sister give birth 5 years ago and see what happened with her - the fact she was ignored and not given pain relief / the fact she suffered a double prolapse, / the fact she had severe PND and the birth debrief only worsened her feelings as she was told it was a 'text book birth' and they wouldn't guarantee her a C-section if she was to try again....... 5 years later she still has PTSD and can't talk about the birth without crying and says she would never have another child - i saw all of this, so I am terrified beyond belief of having no control and medical professionals 'doing things to me against my will'.
I also have PMDD which means I'm currently on AD's for 8-10 days a month, but the rest of the time, I'm absolutely 'normal' ... as it ramps up to my period, my mood crashes extremely badly - if you get pregnant, the hormones ramp up even more.
I've decided that until something changes (change in thinking / change in mood / change in something else), I don't think trying to go through pregnancy is worth it - I'm very grateful to have the life I have with incredibly supportive family and friends and I think that's enough 
One thing to remember when you feel very low is that.... You made that decision because it was the RIGHT thing to do at the time - you didn't feel yourself and you couldn't cope with how you felt... how is that your fault? If you didn't make that decision, there is a chance you wouldn't be here now, and how would that be the right thing, for you or for anyone? It might seem different now, now that the fog has lifted and I totally get that - as sometimes I think 'It wasn't that bad, was it?'
But actually, it was.... it was the worst time of my entire life - When you're in that horrible, horrible mood, you'd give anything for someone to take it away from you.
Before getting pregnant again (and I thought the same), perhaps give it some time - work though things, perhaps talk to a counsellor? just take things day to day.... and perhaps in a few months you'll feel it's the right time to try again, then again - you might feel that actually, you're happy with what you have at the moment.
There sadly isn't a definitive right or wrong way to do things, but I would urge you to give it time and be kind to yourself and don't beat yourself up.