Hi There,
I'm taking omeprazole 40mg, but it's a proton pump inhibiter which means its reduces the about of acid in you stomach it shouldn't be causing any sleeplessness, but it is a rare side affect. I'd be looking so something else or ask you doctor.
Can't answer other that to say do a search here and/or on the web for side effects of omepraole. If that is a possible side effect discuss with your prescribing doctor you may be able to get help from some other medication.