Could someone help me out with the below?

Once in a while I doze off in front of the television or sometimes doze off in the class which could last for 7 seconds and during that period pictures start appearing in my thoughts. Yesterday as I dozed off in the class towards the end of the lecture I saw a bathroom with foam on the white tile in the bathroom following that I saw water running from the tap then I immediately then I regained myself as this lasted for about 5 seconds. Could someone explain to me what experience I was going through. When one dozes off is one in a period of sleeping because to dream I believe one has to be asleep. Was I in a state of dreaming or what is it called when one dozes off. Many a times when I doze off pictures start appearing to me like messages for example I see someone giving me a bunch of flower, sometimes a bag of salt or a glass of water or seeing light in the corrider. What are all these experiences.