What is wrong with my camera?

I went through the same thing a couple of months ago with my used T4i.

I do mostly macrophotography at 1:1 or greater.  As I started to increase the magnification while experimenting with equipment, I started noticing streaks in my focus stacks.

I thought it was movement, but people on another forum explained to me that it was dirt on the sensor.

Unfortunately, the Cleveland, Oho area isn't the best for serious photography gear and accessories, so I had to make do with inferior cleaning products until the good stuff arrived from Amazon.

I highly advise you to get the best stuff you can afford, since trying to clean my sensor with the cheap (and only) stuff available at my local camera stores was an exercise in frustration.  I was literally just moving the contaminants around.  I went through almost a complete pack of cheap swabs without eliminating the spots.

When my good fluid, swabs and blower arrived, I had the sensor clean with the use of only two good swabs.

Following directions on forums and in YouTube, you can clean your own sensor.  Just make sure you buy the good stuff.  Otherwise, you'll accomplish little besides getting frustrated.

A tip:

As noted, you can take a picture of the sky or a piece of blank paper to see the spots on the sensor.  However a lot of instructions leave out a step.  If you just look at that image, it's hard to see the dirt.  If however you run the image through something like Elements and invert the colors, the dirt leaps out in the picture.  I think the command in Elements is F12, but don't remember for sure.