Lansoprazole & Acute Diarrhoea

I'm on Lansoprazole - the smallest dose - for gastritis and acid reflux and I just know instinctively it's doing me as much harm as good - it does help with the reflux, but causes terrible bouts of diarrhoea - I suffered for years with chronic IBS before I started taking it. Ranitidine didn't work and I can't take Omeprazole due to some contra-indications regarding the fact that I'm taking Diazepam. I'm sick of spending whole mornings rushing to the loo - is anybody else having this problem? It means I can't arrange morning appointments - I'm agoraphobic anyway and they are difficult enough without the added problem of the diarrhoea. Today is the second bad bout of 'the runs' I've had this week - spent all Monday morning on the loo and the same today. Anxiety and depression make my life intolerable anyway and these physical symptoms only make matters worse. Life isn't really worth living with this all the time.