Life can be stressful. Planning a wedding can add to that stress. Deep breathing.
A day meant to celebrate should not make your life miserable. If you are high-anxiety person (like me) consider getting a wedding planner. If money troubles send you in to a panic attack, go super simple, or elope. Hate public speaking? Why not due a private ceremony and then a bigger reception so the all eyes on you part has less eyes. No matter what your situation there is a way to make your wedding, and planning, enjoyable.
An easy way to cut down on stress is to start the planning process early, and casually. Don't pay any attention to the "wedding planning timeline" stuff you see. Well... If you want a dress from a big name designer, a super popular venue, the best caterer in the county, or other things along those lines then those timelines are probably about right. But if that isn't you then the timeline you use is unique to your situation. As soon as is comfortable laying out your ideal "when to get what done" list is good to keep organized, but don't let that list be a source of anxiety.
I let that list be a source of anxiety. I came up with a timeline and when W and I didn't stick to it I felt so overwhelmed: I took the list as law. That was silly. Poor W just didn't get why I was so stressed out about the planning. He saw the things we had discussed and agreed apon as "done", while I was in my head like "But we don't have this confermed, or this booked, or these details decided!!!!" The reality of the situation is there are only so many things you can prep ahead of time and it will all work out. I now use my list like a reminder sheet more than anything. I was lucky to have W give me a little perspective on what we can do this far in advance. Also I realized that what is necessary in our little town is different than what all of the magazines tell you about. All of the appointments and pre booking and confirmations months in advance just don't happen here. So be prepared, but over-preparing will just burn you out.