I'm in exactly the same situation and having the same issues. One thing I've done is tell myself over and over that if I was saving up to buy a large item, such as a house or a car, once I had saved up my goal, I would purchase the item and stop saving for it. So, in this case, I've spent my working career saving up to buy my freedom (in a sense), so now I've reached my goal I can stop saving for that and "buy" it, per say. I still have doubts if I think too much, so I'm trying not to think about "the rest of my life", but rather just thinking about "having the summer off work."