Dishwasher seems to b stuck on drain cycle

Question

Hi my dishwasher is 3 years old never had a problem until now. I loaded the dishwasher switched it on and it was making a sucking/glugging noise as if it was trying to drain although there was no water in the bottom. I wondered if there was a blockage further down and poured a few pans of water in which disappeared immediately but then it carried on making this sound. Our model only has 5 buttons - on/off switch and 3 programmes and rinse only so I don't know if it has stopped midcycle although the previous time I used it earlier in the day I didn't notice any probs. thanks for any advice before I have to call the repairman - by the way I'm no DIYer!