Is it normal to still be feeling sad?

I am 29 yrs old, and about 3-4 months ago I broke off a relationship I was in for 2 years. I still feel extremely hurt and saddened by the situation and really miss my ex. Sometimes I wish we were back together or that I did things differently. The relationship was not a very healthy one on both of our parts and I ended for what I know are the right reasons, but I feel like I didn't give it a real opportunity to change or get better. I know my mistakes of not being trusting and his carelessness turned into a lot of anger, resentment, and finger pointing. It hurts alot to see him with someone else and wonder if they are happy. I have tried to keep myself busy through work and family but I don;t have alot of friends, I don't like to go out or be in crowded situations, so I usually spend my nights home alone or with a few select people. I tried dating but that didn't work out and still can't keep my mind off my ex. Also, some of these feelings are brought on because I am ready to settle down, have kids, etc. Any advice is appreciated. thanks.