What you may want to upgrade to will depend to some degree on what lenses you currently own. If, however, you're not too heavily invested in a particular brand (lenses, other peripheral accessories, etc), then I'd suggest you MAKE the leap of faith and check out the Nikon D7100 and the Nikon D7200, compare FEATURES that you WILL use, and compare costs.
Normally, I'd suggest the Nikon D5200, which is the one camera that is worth ever dime insofar as features per dollar. But, you need something that you can grow into, not a mid-range entry-level camera like the D5200, as excellent as it is and how well-built it is. You need something that will allow you to grow and learn for a few years. Regardless, either the D7100 or D7200 will keep you occupied and happy for a number of years. Go to any big camera shop nearest you, ask to see both, hold them both in your hands, compare the ergonomics and how easy it is to reach the buttons, knobs, wheels, etc., for the features, functions and options before deciding. Ask the counter rep to explain the difference, the advantages and disadvantages of each. Be well informed before deciding so you won't have any future regrets.
Whether you choose Canon or Nikon will be up to your personal likes and dislikes but also consider this: Canon and Nikon have the widest variety of lenses for your future needs... that is mighty important, considering that there are other camera brands that also make great cameras their lens variety is limited because they're too expensive or they simply don't have the wide variety to choose from.
When you do get your camera, do yourself a favor, READ the camera's Instructions Manual so you'll be familiar with all the features, functions and options, where they are, when and how to use them so you can have full advantage of what the camera offers to assist you in getting the best possible images. Good luck and best wishes.