A few things to keep in mind:
- the Cessna 152 (and its big brother the 172) is a docile, foregiving aircraft with an outstanding safety record. While it is possible to kill yourself in one, you must work very, very hard to do so;
- if you are flying on your own and the weather changes, you can usually make a precautionary landing somewhere and seek advice. In the worst case you will leave the aircraft stranded at a 'foreign' airport and seek ground transportation home: which would be inconvenient, but no disaster. No reputable flying school will criticize a low-time renter pilot for such a decision;
- if you inadvertantly enter restricted airspace, the worst that will happen is that you will be fined or have your license suspended: not fun, but not the end of the world either. More likely than not, your conduct would be excused with a warning;
- the statistical odds of losing a modern engine are remote. Most engine failures are the result of fuel starvation / mismangement, which you will not experience given that your flights are relatively short and the 152 has a very simple fuel system;
- if the engine does quit and will not restart, the 152 has a low stall speed and if you don't panic you will certainly be able to force land, or at worst effect a crash landing that you will walk away from;
- if you are told to use the other runway, you may perhaps screw up part of the procedure but you will still land safely (it's just another runway, no big deal).
Hopes this keeps some of your fears in perspective.
MLS
P.S. Three apt quotations:
"Do not anticipate trouble or worry about what may never happen. Keep in the sunlight." (Benjamin Franklin)
"The greatest mistake you can make in life is to be continually fearing you will make one." (Elbert Hubbard)
"My life has been full of terrible misfortunes most of which never happened." (Michel de Montaigne)