I feel the same way. I upgraded from my D40 to a D5100 without much thought. But it's been six months since my D5100 broke and I have yet to replace it.
Over the last few years much as changed in the interchangeable lens camera market. The so-called "mirrorless" cameras have become quite capable and in many areas are surpassing the best DSLRs. I've rented and tried many of these cameras1.
My indecision is because I am not sure buying a new Nikon -- I considered the D500 -- is the right choice. I am more informed about the capabilities of other camera brands than I was before previous buying decision. Perhaps I should look elsewhere.