i-94 question Germany US Mexico HELP!!

[ioweyouonebuck]

I currently do not have an I-94 card. I do not recollect receiving one. On January 5th, I arrived in the United States from Germany. My passport stamping shows my entry to Dallas. I stayed in the US until March 21st when I left for a trip to Cancun, Mexico. I returned back in the US on March 23rd. I show the March 23rd stamping in my passport.
I don't have an I-94 form. Is this a problem?
What do I need to do?
Where in this process would I have turned in the I-94 form?
Why did I not receive an I-94 after coming back from Mexico?
Please help

[immihelp]

Read 'Paper I-94W' paragraph at https://www.immihelp.com/esta-electr...authorization/