I think you've got the right idea.
Do a test though- clean the lens and take a photo (while sober

) of a object that isn't moving, while steadying the iPhone on a table/counter or something that also isn't moving/vibrating. If the photo comes out clear, then it's you. If it isn't clear, then there is probably something wrong with your iPhone and I would take it to an Apple Store and get it replaced. That is, unless you've caused damage to it somehow- they probably won't replace it if you've caused the damage yourself.