Hello and welcome to NeuroTalk.
Goodness, you're only 19 and have had a lot of concussions. You probably have multiple concussion syndrome.
Here is a link about that.
http://emedicine.medscape.com/article/92189-overview
Your symptoms are telling you something. Your injured brain is trying to heal and your sports are not going to be condusive to healing.
You only get one brain. I hope you will rethink your involvement in the contact sports you enjoy.
Read the vitamin sticky at the top and start with that and good nutrition for some brain healing.
All for now
Poetrymom