But don't fret!
Pesach does not have to be as scary as everyone makes it sound.
Really, truly... preparing for Pesach is not that hard. If you don't have children and regularly sorta-clean your house, you should be able to clean for it in an hour or two. (Kashering the kitchen may or may not take significantly longer, depending on your kitchen and what you believe is required to kasher it for Pesach.)
1. Crumbs are not a "kezayit." They're garbage. Ask Aish if you don't believe me.
2. Neither you nor the dog will be eating any chametz that may or may not exist under your fridge, car seat, or heavy furniture.
3. Don't take "unfit even for a dog to eat" quite so literally. Case in point: the standard is not "poisonous" in most communities. As Rabbi Soloveitchik famously said about a dog who ate toothpaste, "Your dog is crazy." As interpreted by rabbis I know, "You trust a dog to tell you what's fit for a dog to eat?!"
4. Just because you're required to search for chametz doesn't mean you actually have to FIND any. You're not required to hide any. If you insist on hiding some token chametz, please remember to write down where you hid them (and don't make them bigger than a kezayit!).
5. If you pay a person to spend hours vacuuming the pages of your library, I will nominate you for involuntary commitment to a psychiatric ward.
See? Aren't you more relieved already?
I'm not the only person who says that Pesach prep should not give you a mental breakdown.
If you're uncertain about your community's "theoretical" standards for Pesach (because many OCD-inclined people choose this mitzvah for their entry to the Extreme Machmir Awards), discuss these posts with a friend, mentor, your rabbi, or any other Passover-celebrating Jew you may have access to (if you lack those other resources).
Fair warning: if you're loud-mouthed about how relaxed your Pesach prep was, don't be surprised if people refuse to eat in your house. They could even refuse on principle if you "follow the rules" but your method looks "different" (for example, kashering your kitchen counters instead of covering them). But on the other hand, never be surprised if someone refuses to eat in your house during Pesach. People be cray-cray. A fair number of people refuse to eat in anyone's house during Pesach.
#ProTip: the best part about converting is that you get to choose your minhag. Trust the Sephardi about kitniyot!