My 15 year old son has ADD and Aspergers and my 11 year old daughter has ADHD.
We have a very stressful home environment at the moment and would appreciate any information on how to cope better.
As to your question, while I have never experienced what you are I have encountered many parents in a similar situation. Many find help and relief by sharing with others in similar situations through the various Aspergers/ADHD support groups, I hope you have one close by you. Because I have limited experience in the area I can only offer a more general response.
Firstly, celebrate the positives. In any intensely emotional situation it is easy to become so absorbed in coping and responding that it is easy for the joyful moments, that ought to bring relief, to slip by almost unnoticed. I am sure there are moments every day when your son or daughter do or say (or sometimes don’t do or say) things that surprise or amuse you. Depending on the preceding behaviour it could be difficult to do this, but whenever possible make a conscious effort to enjoy those moments and lock them away in your memory.
Secondly, remember that your kids are teenagers too, much of the behaviour that makes life tense now is a perfectly natural part of adolescent development. It doesn’t make the behaviour any less irritating or stress inducing, it just means that as your children mature the extremes of behaviour will moderate and life will be more gentle.
And thirdly, focus on the medium to long term. This is probably small comfort, but you are almost certainly going through the most difficult time you will ever have with your children. As you consistently and lovingly parent now the attitudes and stability you hope to see in your children will gradually take root and grow. When they are in their late teens and early twenties they will probably not understand the difficulties they caused for you but you and they will enjoy the relationship you long for.