I can well understand your feelings at this time, given the fact that your manager is treating you in the way that he is doing at this time and while you feel that you are not doing as well as you should be, having worked for the organisation for as long as you have.
Firstly, I do not feel that that you should necessarily be looking for a new position, but rather looking at this time to deal with the issues at hand, namely your late-coming and the standard of your work.
Let us deal with the late-coming. I am certain that you realise, and it has probably been pointed out to you on a number of occasions, that you are transgressing the rules of the organisation, in addition to placing unnecessary stress and extra work on management and your colleagues who have to “cover” for you if there are urgent matters to attend to when you are late and not able to attend to them yourself. I think that you should make every effort to ensure that this does not occur again – remember, that you could lay yourself open to disciplinary steps and you do not want this to happen as your current employer would maybe xxxxxxxxxxxxxxxDoes this stem from the fact that you are able to do your job with, as they say, with your eyes closed. This could also be the reason as to why you are making what I am sure are silly mistakes – you are so used to carrying out the tasks and duties that you are making small errors, which your boss is prepared to overlook. And here lies the crux of the matter.
I am certain that you realise under other circumstances, you might have been hauled over the coals for these mistakes/error/oversights and, who knows, action may have been taken against you if there were serious consequences for the company.
The fact that this has not happened is more than likely because your boss appreciates the work that you do, he knows that you know the systems and procedures in the organisation better than most people and he doesn’t really want to lose you.
So, there are a few things that you can/should do. In the first instance, you need to make very (and I mean EVERY) effort not to make the mistakes that are creeping into your work – remember that unless you do this and you do decide to leave, someone will need to provide a reference – and you do not want the message to a prospective employer to be that you are careless and you mistakes.
Secondly, I think that you should take the opportunity of discussing your situation with your boss – and do so when he/everyone can see that these small errors are a thing of the past. You can say that you have been trying really hard to ensure that your work is always of the very highest standard – and then ask him if there are any small tasks and duties that you can do that are in a part of the company where you feel that you might like to work. It is always good to see where you can move in an organisation (you have been there for a long time, you know how the company “works”) and so ensure some continuity in your working environment. You can then begin to expand your horizons within the company.
Thirdly, you should consider tackling some further studies in a field which interests you and which, if necessary you can use in the company, or outside if you should decide to leave.
It is always necessary to carefully consider what you can do to correct a situation, rather than just deciding to leave without having thought through all the implications and consequences.
This is a broad sweep through your question – please do submit another question to the website if you require any further assistance or information.
Good luck with your future endeavours!