It sounds as if you might have obsessive compulsive disorder (OCD). A diagnostic interview with a mental health professional could determine your diagnosis. Antidepressants are one form of treatment for OCD but there are others. One of the most effective treatments for OCD is a behavioral-based treatment called exposure and response prevention therapy (ERP). In some cases, ERP can effectively cure individuals of their OCD. Cognitive behavioral therapy has also been shown to be effective for OCD.
The arts and entertainment channel A&E produces a reality television show about OCD called Obsessed. The show features therapists providing ERP treatment to their clients. I would suggest going to their website to view one of their television shows. It is not currently being shown on television at this time but you can view clips or entire episodes online. Watching the television show should not be considered a substitute for treatment but it will give you the opportunity to learn more about the basics of ERP therapy.
I would also encourage you to seek help for your problem. There is nothing to be ashamed of. Millions of people seek help for problems that are very similar to yours. OCD (if that would turn out to be your diagnosis) is relatively common and, as I described above, effective treatments exist. In addition, the sooner you begin treatment the sooner you can deal with this problem and eradicate it from your life. This is particularly important with a possible diagnosis of OCD because if left untreated it tends to become more severe over time. What this means in practical terms is that you may find yourself engaged in your checking behavior more often and for longer periods of time. Putting off treatment is not recommended.
Click on the find help tab at the top this page to locate a therapist in your community. Choose a therapist who specializes in the treatment of OCD and has been trained to provide ERP therapy. That would be the most efficient way to treat OCD. I wish you the best. Please take care.