I understand that this question is almost a year old now, but the topic is timeless so I will post my advice here for yourself if you're still having problems and for anybody else who comes across this problem.
I've been in this position before and I did the worst thing possible: I didn't tell my manager and I quit 'out of the blue' when the anxiety became too much.
The plan of action should be the following:
- Tell your manager you're having problems with anxiety. If you don't want to be this open with your manager then go to H.R.
- Go to a GP and pursue professional help until you've got a handle on the anxiety (this can take just a few months, a few years, or longer). Don't be afraid to request different counsellors if you aren't making any progress with your current one.
- Update your manager with how you're getting on every few weeks, or more often if constructive.
Both your employer and yourself should treat anxiety as any other medical condition. It shouldn't be brushed under the carpet, it shouldn't be ignored, it needs to be addressed. It will only get worse if you don't seek help. Anxiety can easily take up most, if not all of one's mental energy. It's horrible because you believe all the things that could go wrong.
Once you tell your manager you can do a number of things:
- Agree on changing your workload. Just like taking time off work for a back injury, changing your workload whilst suffering from clinical anxiety should be standard practice.
- Agree time off for medical appointments
- Take the weight off your damn shoulders!
Once you've taken the heat off and started talking regularly to a health professional, chances are the counsellor/doctor will ask you to stress yourself a bit at work again in a controlled manner so as to test and monitor your response. By stressing yourself in a controlled environment you're learning to manage the anxiety. It's like physiotherapy for a broken foot. This is how you overcome it. You'll apply stress, learn to manage it, then be able to apply more stress, manage that and so on. Keep working at it and within no time you'll be back up to full speed, working more efficiently than ever before.
Co-workers don't need to know. Just tell your manager you don't want others to know. If anyone asks, joke, laugh, brush it off with humour. Tell them to stop being such a gossiper.
Anxiety can be handled and it does not mean you are bad at your job. In fact it will make you an awful lot stronger when you get a handle on it. It will make you an excellent manager in the future because you'll know first hand these problems. Learning how to handle your anxiety can make you a lot more resilient than others who have never experienced it (yet).
If your manager doesn't respect the illness then they're a bad manager - by definition. Go to HR and if they don't respect it then leave the damn company, they don't deserve to hold on to you as an asset. In this day and age though, this is highly unlikely to be the case. Good luck, it's quite a journey, but you won't be alone. The more people you'll talk to about the problem, the more people will talk to you about their experience - a surprising number of people will talk to you about their history of anxiety. It's very common. I seem to remember a figure of about 20% of people have clinical anxiety of varying degrees at any one point. Hope this helps!