I have shot film before, never black and white though. I also haven't ever developed a film before, neither did I this time.
I used Ilford Delta 400 and I shot it at rated ISO (at least I think I did). I just got the pictures back from the shop and they all look like this: https://imgur.com/a/E5WmP
Now I'm wondering, what went wrong? Was my exposure that off for every picture (for example I forgot what the film ISO was), there's something wrong with my camera (I've shot with it before, It's an old unmaintained fed-2, I know there are some leaks, but haven't had nothing like this before) or is there something wrong with the way the film was developed? I can probably blame my camera for these light and dark bands, but I've never gotten this much noise even with really bad under or over exposure.
If it's the development issue, then I'd know what to specify the next time I have an black and white film to develop. If it something I did wrong, I'd like to know.