If you did not really want to abort in the first place, then having the abortion is absolutely not the right decision for you. I am sorry that you had to feel that this was the only option for you, at least at that time. It doesn't necessarily mean that your husband was wrong, but rather that he didn't understand how serious this issue was for you.
You, on the other hand, you have a problem. You are stuck with guilt feelings over something you can't change, and over having been led into a situation you didn't want. I suspect that you worry and think about this all the time, and that nothing ever changes; rather that you keep on feeling horrible about it. I don't know what your feelings are towards your husband about this, but I suspect that he might begin to feel that you should have gotten over it by now, maybe even feeling that you are hysterical about this, which could add to your stress.
You really are stuck and can't work out a solution to come to terms with what happened.
Likely the way out of this is through counseling. This is a way to have help exploring exactly what your feelings and emotions are, and why they affect ou the way they do, and also a way to work through what you can change to feel better without denial or trying to "make it better" without having your emotions follow with the "logic."
your situation is what counselors do best, helping people work through situations where they are "stuck," especially if it affects all of their life around them as well.
Now, counseling does cost money, but if you have health insurance, it should cover some counseling, at leats. But be careful. Many insurance/hmno plans have serious restrictions in the type and amount of counseling available.
Or, if you don't have the funds, your community should have some form of free or sliding-scale clinic.
There is also the option of going to your church and talk with the minister about it, as they all have some form of counseling training in seminary. But a word of caution. If your church is one who openly condemn abortion, you could run into somebody who feel that you *should* suffer and/or will load even more guilt onto you. That is why I generally advice more professional counseling in these cases.