Is It Safe To Give Multiple Antibiotics To Children For Strep Throat?

My 4 year old got strep throat a few weeks back and was prescribed Amoxicillin. After taking his 10 day dosage it for only 6 days he broke out in hives and had to be rushed to the hospital. They took him off the Amoxicillin and gave him Azithromycin to take for five days. He was unable to take the Azithromycin because of the taste. He threw it up the first day and the second day refused to take it all together. Even with it mixed inside of fluids and foods. His Dr. then prescribed him Cephalexin to take for 10 days. He has taken the Cephalexin fine mixed inside of his juices and has been taking it for 5 days now. My question is that, is there any side effects to taking so many different antibiotics in such a short period of time like this? He has had moments in the past where he has acted out and had tantrums, but is usually easy to calm down. He went through a hitting stage when he was younger where when he was angry he would hit and slap. But that ended long ago and he has calmed down quite a bit over the years and came to understand that hitting is bad and he stopped. But lately he has been having lots of tantrums and outburst. He is showing lots of anger and I have been having a hard time calming him down. He is definitely acting very different than he was before getting strep throat and being put on so many different antibiotics. He is no longer sick and the hives have completely disappeared. He has no fever as well. But he is acting in ways that are definitely not normal behavior for him. Is it possible that he could be acting this way from the medications? He has never had to take so much medicine before so I am curious if his behavior problems could be from the antibiotics. Thanks.