Look at your y-axis. This is your absorbance. Do you see how each one of your data points matches an absorbance on your y-axis? Now look at your x-axis. This is your concentration. Does each data point match one of your concentrations? They don't. You'll notice the x-axis value for each of your data points is 1, 2, 3, 4. They should be 0.000002, 0.000004, 0.000006, 0.00001. If they don't have that on the x-axis, then you set your graph up wrong.

It looks like you didn't specify values for your x-axis, so Excel just filled in generic values 1, 2, 3, 4. You need to specify values for the x-axis. To do this, right click on one of your data points, then click "select data." There is an option there to edit a series, and you can then pick your x-axis and y-axis values as you please. Try that out.

It does look like you got your trendline down, right, though. So that's good. You just need to fix your x-axis.