Have an honest look at yourself. Are you doing quality work? Are you working hard? We cannot answer those questions, but they make a huge difference in how you should proceed.
If you are working hard, but just are not getting it done, then it is probably time to look for a different role better suited for your skillset(or to get some training, or even to just listen to the feedback from your coach). If you are not working hard, and turning in low quality work, then its solely on you to turn things around.
If you are working hard, and feel like you are turning in high quality work, then you need to stand up for yourself and a conversation with your coach about expectations, results, and what you are/are not willing to do.
Again though, outside opinions often are based on flawed perceptions. You know whether you are getting the job done or not. Your opinion of your work is the only one that should truly matter(to you).
If you want advice on how to handle a-hole co-workers, the best advice I can give you is to do three things.
1) Ignore their petty drama while putting money into the 'stache.
2) Work hard, do quality work, and always make sure things are document correctly.
3) Do not put up with any shenanigans, and walk away if you have to.