To judge market reaction over a potential "Brexit" is to assume the end of days is coming. 

But Jim Cramer, portfolio manager of the Action Alerts PLUS Charitable Trustsaid a British exit from the European Union isn't a be-all end-all for the region nor global markets. 

"I want to urge people to not be too pessimistic," said Cramer in an interview at the New York Stock Exchange on Tuesday morning. 

European and U.S. markets have been under pressure so far this week due to the looming U.K. referendum in which Great Britain will decide upon whether to remain in the EU. The "leave" option currently has a seven-point lead among voters in the latest poll. A "Brexit" would have major economic and political implications for the stability of the EU.

Those in favor of leaving the EU argued that the body's bureaucratic reach in recent decades has reduced British agency. Those who oppose an exit argued that like-minded European countries ought to remain together to influence global politics and the economy. 

"This is not that terrible moment in our country when we thought we might default on Treasuries," continued Cramer. "This is not October, November of 2011 when Italy's bonds were at 7%. Remember when we used to talk about the PIIGS -- Portugal, Italy, Ireland, Greece and Spain -- they were all going to go under. It's not like that."

Debates raged in the late 2000s, during the height of the global financial crisis, over whether to bail out the PIIGS nations who were unable to refinance their own government debt nor bail out their banks. Cramer noted the economic situation now is not nearly so dire. 

"People are making it out like" the PIIGS crisis, said Cramer. "This is not an artificial issue but just don't be too pessimistic ... It does not pay to be as pessimistic as they are in Europe." 

U.K. citizens will head to the polls on June 23.