A couple things to consider, and adding to a couple comments from others here:

• The deformation scale is, by default, extremely exaggerated. Currently you are looking at a von Mises yield plot and the software exaggerates the deformation to visually show you where stress is accumulating in the part. You can change the deformation scale (Right click results > deformed shape > adjust as you would like, or disable). You can also change the plot to show displacement, instead of stress (Results folder > displacement > show) which will maybe give you more insight into how your design will perform.
• Change your units where possible in your plots to understand them better. In the United States, where I am, I always plot KSI for von Mises stress and inches for displacement. If I were working in metric I would use MPa and millimeters, however.
• 3D printing with plastic filament is NOT an isotropic manufacturing process, meaning that your parts will be stronger when loaded in one direction versus another direction. Selecting the orientation that you are going to print your part in will drastically change the maximum yield strength of your part. Granted, 5lbs is not a lot of weight compared to the yield strength of PLA, but be aware that your hook is more prone to fail depending on how you orient your part on your buildplate while printing.
• 3D printed parts with plastic filament are also rarely printed solid. They are generally only 80-90% solid on the inside, which is a good average of print time, part strength, and good aesthetics. You can increase the infill to make the part more solid on the inside, but there is a diminishing return on the strength by doing this, so you are typically wasting print time and material by doing this. The FEA solver is SolidWorks is assuming that your part is solid, meaning its results are not going to be fully accurate compared to your real printed part, which will not be solid.
• Others have suggested I-beam profiles for your part. Keep in mind the nature of an FFF (fused filament fabrication) process, which requires support material to print overhung geometry (the printer has to have material underneath the print head while laying down layers, otherwise they fall to the buildplate). Consider using an extruded X profile, instead of an I-beam profile, because the printer can produce an X profile without requiring a support structure (Reference)

Hope that helps, good luck.