Is my dog having seizures?Whats wrong with him?

I have a Shar pei puppy dog about 7 months old or so , About a few months ago he has been having these weird attacks , But only when hes asleep He sleeps normally then about 5 minutes into his sleep he starts twitching and whimpering and moving i call his name out and he keeps at it till i call out one more time and he wakes up and it stops , Hes always been a very thin dog As much as he his fed he stays pretty thin , He is healthy we always take him on walks and we even let him rest in our balcony so he could get some sun and fresh air , And yesterday while h was pooping it took him quite some time to finish he was making this weird nose but he only did it once it was like a whimper sort of but it sounded as if it came from his stomach.Today he vomited twice he vomited a sort of clear,mucus like substance.He eats perfectly we serve him to scoops of food and clean water.We stopped feeding him ham and other stuff , As an additional thing i think is causing this is because about a week or two ago my mom was preparing steaks and she laid to steak on a plate on the counter and turned to cook more , My dog ate them both up . Do you think the steak is a problem?What do you think is happening with my dog?Hes also been very itchy lately but has no fleas or ticks . Please Respond im very very concerned!