|Your manager might call this change “job enrichment,” but the only enrichment is for your company as a result of the elimination of one position.
In fact, your manager is not even using this term correctly. Job enrichment technically means providing an employee with more autonomy, decision-making, and managerial responsibilities in handling his or her job. Dumping more of the same work does not qualify as enrichment.
Part of the problem is that you have apparently not shown any signs of assertiveness or concern. Regardless of whatever may be behind your lack of responsiveness, the longer you go without saying anything, the more you and your work will suffer.
You should meet with your manager to discuss this situation, and do so by asking questions rather than issuing demands. For example, since the work is already piling up, ask him for the priorities on your projects since some will now be delayed as a result of the increased workload. And speaking of that workload, ask him if there is a plan is to adjust your pay now that you are essentially handling two jobs.
This changeover could open several doors for you, but if you fail to take action, it could lead to an exit.