i suppose the only way you could do it would be to go to your doctor and tell them that work is causing you unnecessary stress and that you can't cope and see if they sign you off... as to weather it would cause you more trouble is something only you can really answer.
Firstl,y financially would you miss out if you were signed off sick? but then you did say this wouldnt be an issue as you get full pay (would you not get SSP once you get signed off for more than a week?), secondly you have to consider if it would really be worth it from your point of view.
I honestly cant stand work and i have another 5 weeks left until i start my maternity leave and even though i cant wait to go on maternity leave, plus the fact that i can leave early if i wish (i work for my dad and he has told me i can leave whenever i want basically and has even advised me to leave abit early than in 5 weeks times) i know it would drive me crazy sitting at home waiting for baby to arrive if i were to leave work now... Sure it would be nice to have the time off for a while, sit at home and mong out watching jezza lol, but weeks of just sitting around waiting would annoy me after awhile and i think i'd rather be at work!! (i know this was true of my sister in law aswell who left work as early as she could but later regretted it as she hated sitting around and waiting for baby and she said it just dragged things out and made her feel depressed)
If you honestly feel like you cant go on at work and that the stress is too much for you and making you sick, then i'd say go to your doctor and see if they will sign you off on health grounds, but if its more of a case of 'i might be able to get signed off, im not keen on work, so why not' (not ment in a nasty way there but sometimes when you know you can 'get out' of work then the temptation is there to go ahead and do it), i'd say think about it hard as you might even regret it after a good few weeks of sitting about at home, jsut waiting and getting bored.
I think this is your choice and you have to make it based on how you honestly feel. Whatever you do, goodluck
xx