I regret having an abortion..?

I'm nearly 17 and my boyfriend is 19 and we've been in a strong relationship for 13 months. I found out I was ten weeks pregnant in early June. I was feeling sick and was extremely tired, but I was doing my GCSE's at the time, and also I lost my nan, which is an on-going heartache, so I put it down to stress (as I do use contraception all the time). And so we decided to go for an abortion and yeah I was sad but I knew it was the right thing to do because of our situation etc, and two and a half weeks on I feel so sad. Whenever me and my boyfriend go to town or somewhere, we see babies everywhere and it kills me. We always speak of what we could of have, and we figured out the date of the birth and I've had dreams of having a baby. It really hurts me inside and I feel so bad. Any advice?