From the symptoms that your are facing at the moment it does look like you are suffering from depression. In most cases the patents has symptoms of Anxiety and Panic attacks intermittently along with sleep problems due to excessive negative thinking. The symptoms that you are facing is due to excessive stress that you are facing in your life or some times its genetically programmed to do so. This part is not under out control and hence you should not feel bad about it. There are neurotransmitters in the brains(chemicals) which regulate the daily function they have decreased hence the medication to put thing right by correction of the chemicals, one may be kept on these medications for about 6 months to a year depending on the progress which shall be decided by the consulting psychiatrist. the medication are always started in low dose and slowly increased to see for any side effects it may have and the dose at which you may respond. These tablets will definitely help you to get better but if you do face side effects like nausea , drymouth, sleeplessness , dizziness inform your doctor any way not every one will experience the side effects. in case you do you can always discuss with your doctor. These tablets do take time to work and to improve your condition may take 2-3 weeks time. if you got a good response in a short time then these tablets are well suited for you. about the negative thoughts they will fade away automatically during the course of treatment and with counseling