Diagnosis for Recurrent pericarditis & pleurisy

I have been suffering for 5-6 years withs this problem of continual pericarditis & pleureisy and I desperately could do with some help. I am now 41 but when I was 35 I went through a stage after divorce of 'catching up' on my lost wild years. I went out with my friends a drank heavily for a few years and stupidly even tried cocaine on and off for about a year.
I started to get Atrial Fibrillation the day after heavy nights of drinking which was painful and very scary. I always ended up in hospital and my heart rate would go over 300 beats per minute easily. They would inject me with Amiodrone to calm my heart down which worked. I calmed down stopped drinking heavily at weekends and never touched cocaine again.
Less than a year later I started to get pains in my chest which was like a hot liquid inside my chest and extremely uncomfortable pain around my heart area. I didnt know what it was until I suffered SVT (Super Venticular Tachycardia) whilst the inflammation was inside my chest and I was in Germany. I was rushed into a German hospital where they diagnosed Myocarditis & pericarditis with an effusion around my heart, which had caused my heart to go into the fast rythm again over 300 beats per minute.
The problem I have had since is that is has kept coming back and ruined my life. The doctors at poole hospital are useless. They say my symptoms are like Lupus but not Lupus. They have tried me on Cellcept, Colchicine, Plaquenil, Azathioprine & even cyclophosphamide treatment at the beginning but nothing ever works. The only thing that ever works is the Steriods (prednisolone) but this just dampens down my immune system to stop it from attacking my lungs and heart.
Every time I get my steriods down to a low dose it comes flooding back and my heart and lungs get inflammed and im in excrutiating pain. Just recently I got my steriods down to 4mg a day but I got a coldsore (Herpes Simplex) and then boom! back came the inflammation inside. My girlfriend also got a sore throat and viral infection at the same time. I think that when my steriods get low I am succeptable to any infections going and when this happens my immune system goes into overdrive attacking all it can in my body. I then have to take more steriods normally back upto 20-25mg a day which starts to help the inflammation and get the pericarditis and pleurisy down after a week.
The Heart unit at Poole are useless (even the top specialist's has heart problems and is always off work so you get a trainee everytime who knows nothing about you), The Reumatologist is as helpful as she can be and has done everything I suppose you should do by prescribing me all these drugs but they dont help. ONLY steriods keeps it at bay but this is not the cure it's just a temporary fix to hold back the storm. I don't want to be on steriods forever which has already taken its toll on my body.
My hope is that someone reading this may have had something like this or is there anyone who can help. Something has caused my immune system to go haywire but it only started happening after I first suffered the Alcohol induced Atrial Fibrillation. Until then I was healthy and energetic but now I am like a hermit.
I feel my doctors are missing something and maybe other treatment could get me back on track.

Here's hoping anyway
Lee