My 2p, quit asap. Start interviewing for the other jobs and enjoy your downtime in between jobs. It's not going to get better for you and now you know what working at an agency is like. Appreciate the lesson and move on.
As far as what your current company feels, consider this. Are you producing at the level you know you could? If not, is it really better for them if you stick around? I just heard an example of this from the Design Details podcast where Kim Bost left Etsy to go to a smaller company in arguably a more socially important field. She wasn't enjoying herself not was she capable of doing her best work so she left after 4 months on good terms. It's better for both sides to quit early.
As far as what your current company feels, consider this. Are you producing at the level you know you could? If not, is it really better for them if you stick around? I just heard an example of this from the Design Details podcast where Kim Bost left Etsy to go to a smaller company in arguably a more socially important field. She wasn't enjoying herself not was she capable of doing her best work so she left after 4 months on good terms. It's better for both sides to quit early.