I feel like everyone (myself included) thinks "Oh, that company/industry has their shit together", spoiler: they don't. One lesson I have to keep reminding myself of and relearning is a large company (even successful ones) doesn't not immediately equate to knowing what they are doing. Imposter syndrome is a huge issue inside the tech industry, I imagine it's even worse for the people on the outside looking in.

Maybe a part-time web development job would work for you? Get your feet wet without having to go full-time right away.

My comments about certifications really boil down to "Don't expect a certification to result in a job or even better standing among other applicants". Being someone who is enjoyable to talk to/work with goes way further in my book. I'll take a "1x" programmer that's easy to work with over a "10x" that's a jerk or has no social skills. Also your "self-taught" skills are probably a lot better than you are giving yourself credit for. I'd bet money you would do better than the majority of new CS grads when it comes to actually producing.