A 2.6 GPA is equivalent to a score of 81, which is a B in most US colleges. It’s not as if you almost failed out of school. It could definitely be better, but people have graduated and gained employment with lower scores.
Is your degree still useful? Yes. Are you employable? Yes. Can you get into grad school? Probably, but it will be harder for you than for someone with a higher GPA. You may not qualify at certain schools or for certain programs with GPA requirements.
What I would do is kick ass until graduation (provided you are not already done) to see if you can get it to go up even a little bit. Upon graduation, find a teaching job. Get a few years of teaching under your belt before applying to grad school. Undergrad GPA matters, but experience looks good and it’ll most likely improve your chances of being accepted into a graduate program. Graduate psych programs are known for being extremely competitive, and child/developmental psych is a popular field of interest, so be prepared for some rejection – be persistent!
I actually don’t think going to grad school right after undergrad is a great idea unless you NEED that higher degree to get a job in your field, such as doctors and lawyers. Companies don’t typically like to hire people with too much education and too little experience. The new graduates seem to expect better pay, but employers don’t want to pay more for people who have never actually done the job.