It’s good that your’e thinking about this, and not to discourage you, but when employers start taking work away or start giving you less to do it may be a sign that your days there are numbered, it is also a tactic that employers use to get employees to leaving willingly, but I agree that you should ask why you were taken off of these projects, it may have nothing to do with your performance and more to do with shifting resources to meet deadlines.
No offense, but you don’t have enough experience or time there to really disagree with their process. Try to remember that the processes that you learn in school are ideals and the processes that you encounter on the job are realities. Not every agency, consultancy, or corp design team will necessarily adhere to the ideal processes that you learned in school, for many reasons. In the working world I’ve found it helpful to identify when and where components of those ideal (or best) practices make sense to plug into a project, and where they don’t.
As far as the unhappy clients, that is typically the fault of the sales rep or account exec not working with development on realistic deliverables in order to set proper expectations. It may also be an project management issue in timeline and resource tracking.
I’d stick it out a while longer, ask questions about anything in order to keep learning, and bank that experience for your next gig if you decide to leave.