out of status! potentially many problems.
If you are in the US as an F-1 student and are not attending classes in the school that provided the I-20, you are out of status and are deportable. In this post-9/11 world, the F-1 student status will be gaining increasing scrutiny. Technically, you should return home immediately or submit to Nebraska Service Center Form I-539, Application to Change/Extend Nonimmigrant Status, to change your status to visitor to let you remain in US with your mother in valid status. This MUST be submitted within a month or so of the beginning of the school period that you were supposed to begin attending. you will need copy of your I-20 and I-94, and passport, a letter of explanation concerning why you did not attend school should help.
In addition, you may apply for permanent residence if your mother is US citizen or permanent resident AND if the visa is "immidiately available." i.e. how old are you & are you married? unmarried child of US citizen under 21 years of age has a visa available, however over 21 year old and other catagories have waiting period. in these other situations, need I-130 filed by your mother and you will have to wait to apply for GC later. In the meantime, you are out of status and are unlawfully present in the US. If you are also employed in the US without authorization you are exacerbating your situation, compounding your inadmissibility factors.