I came to USA on a F1 visa on 2005. I went back to India on 2006 for a visit. But when I came back the immigration stamped my passport and gave me a new I94. I went to my college for all the reentry paperwork but my college didn't entered me into the USCIS sytem or didn't report me to the sevis. (I realized that when I went to my college to get a new I20 on 2008). By 2008 october I was almost done with my program and the college DSO was not very helpful. He told me that I was done with school and told me to leave the USA. I refused and he told me that he will apply for reinstatement. I gave him all the necessary paperwork but he later told me the packet was lost in the mail. Now I graduated recently and I have overstayed my visa. I haven't got any notice or letter from USCIS.
Consult with an immigration attorney immediately. If you are not in school and do not have a corresponding visa, you are out of status and subject to deportation. You may be eligible to adjust your status or if you were issued an I-94 indicating your status is "D/S," you may be able to leave and return without too much hassle.