They paid you close to $10k to work with them on a project related to your OSS. It should have been clear there would be a ton of overlap or a relicensing at this point. You still got to keep your open source stuff open source.
They didn't ask you to quit your job and with a single contract of unspecified scope you really shouldn't have. Did you ask your former employer for your job back?
You made a bunch of bad choices, it happens, you're young, I know I made a ton of my own at your age but they were your choices and not anything done to you.
They paid you close to $10k to work with them on a project related to your OSS. It should have been clear there would be a ton of overlap or a relicensing at this point. You still got to keep your open source stuff open source.
They didn't ask you to quit your job and with a single contract of unspecified scope you really shouldn't have. Did you ask your former employer for your job back?
You made a bunch of bad choices, it happens, you're young, I know I made a ton of my own at your age but they were your choices and not anything done to you.