Toddler with Fainting Like Seizures

Hi, Our son had his first seizure 1 week before his 2nd birthday. Well we think it was a seizure. It was around lunch time and he had stated he was "so tired" but then when asked about lunch he was hungry. So we were eating lunch and then in a moment his face lost all tone and he began to fall off the chair, luckily my husband was able to grab him before he hit the ground. His breathing became shallow and it looked like he was fainting or trying to go to sleep. He was taken to the ER where he still had not really gained his balance for a couple of hours later. He was given a Chest/Head CT Scan along w/ an EEG and everything "looked good". The DR's released him w/ a follow-up and he was doing great until about 3 weeks later where again, it looked like he was going to faint. This time it was at 8:30am and he again stated "I'm so tired" and then just started sliding off the couch. He had another EEG and MRI but again everything looked good. 

His Sympotms seem to be :

Gets Sleepy Like ; Will close eyes for 10-30 secs or will not focus; And then just seems "to come back";  He has 2-3 days where we don't see any sympotoms and then other days where he's had 2 in 1 day; 

Thanks so much for any and all feedback, itmeans so much. This has left me a nervous wreck and I feel so helpless not seeing to have answers.