I am sorry to hear of your struggle.
It is likely that this feeling is not related to the forced vomiting. (Although, if this is something that you do on an frequent or even infrequent basis, it is of course associated with the disorder bulimia and it is important that you talk to your doctor about this so that you can be treated)
It is also not possible that you damaged your brain in any way when you forced yourself to vomit. It is possible that you have a brain disorder
It is more likely that this symptom is occurring as a sign of one of several brain disorders which are commonly known as mental illness, and include diagnosis such as schizophrenia and schizoaffective disorder.
Although I agree that it is important to rule out medical problems, once this is done, you must look at the problem realistically. I understand this can be hard to do, because no one wants to believe that they could possibly be developing a mental illness.
You are at the age when mental illness such as schizophrenia do being to show symptoms. It is very frequently the case that it develops in the first years when the young adult is attempting to live on their own and/or attend college. A preoccupation with the thinking process and sensations is common in the early stages.
Of course we could never diagnose you with this chronic illness, just over the internet. There would be many more details to evaluate.
I would recommend that you see a psychiatrist for evaluation and ongoing monitoring.
While in the past, derealization and the other thought disorders that occur along with mental illness were only partially treatable, since the 1990's new medications have been developed that treat these disorders and if taken diligently one can lead a normal life. The biggest problem can be the denial that such a serious illness could be a possibility.
But keeping an open mind and seeking evaluation with a psychiatrist will allow you to be monitored at started on the appropriate medications. If you do this, then you may never experience the most serious symptoms that can occur with these brain illnesses.
You may find these articles helpful in understanding the potential symptoms of developing mental illness. Again, it is too early and not possible over the internet to tell you for sure this is what you have, this is just one possibility, and something that is better to know about and rule out, rather than to wait for a more serious manifestation.
Feel free to write back to me and let me know your thoughts on this. Please do understand if I don't get back to you immediately, I will as soon as possible. (For example my mouse for the computer has stopped working, and I will have to go now to buy a new one, but will be back in an hour or two)