Being arrested for simple possession of an illegal drug is a charge based on the defendant being a drug user who had no intention to distribute the drug in question. While simple possession of a scheduled drug is illegal, the penalties for possession are much lighter than others.
If you are found in possession of significant quantities of a scheduled drug, or other things such as quantities of cash, drug scales, individual baggies, quantities of drugs divided into different portions, or any other indications that you were intending to distribute the drug, then you will be charged with any number of more serious charges like intent to distribute, or drug trafficking.
If you are charged with an intent to distribute or a trafficking crime, then you need to work with an aggressive attorney as soon as possible who can build a strong defense for your San Diego drug crimes.