AWS and ELB Network throughput limits

My site runs on AWS and uses ELB

I regularly see 2K con-current users, and during these times, requests through my stack would become slow and take a long time to get a response (30s-50s)

None of my servers or database at this time, would show significant load.

Which leads me to believe my issue could be related to ELB. I have added some images of a busy day on my site, which shows graphs of my main ELB. Can you perhaps spot something that would give me insight into my problem?

Thanks!