I was taking Nexium for 2 weeks and it dramatically eased my IBS symptoms; less bloaring and gas, less abdominal pain, normal bowel movements (twice a day). Overall my mood changed and generally feel happier about life 
I read a lot of negative side effects of Nexium and wanted to ask if anyone can advice if taking Nexium once in 2 - 3 days still has these side effects or what period of time is considered to be "safe" to use Nexium.
I too took Nesium for GERD. My physician told me to take it for 14 days (the usual number of days it is taken) and then stop and if my symptoms continued to call him. They did not. GERD was gone and has not come back. I had no negative side effects that caused me concern. If you were going to experience side effects, you usually notice them soon after you start taking the med. I'm very glad you are feeling better.
I took esomeprazole (stronger version of omeprazole which is the drug in nexium) for over a year for chronic gastritis. No side effects.
l have used something similar esomeprazole for 10 years now.