I had peace initially while meditating and then lost it?

I set up a routine to do my meditation where i just watch my thoughts. After some days i found a peace after meditating which continued through out my day. I enjoyed the calmness inside me. Following a stressful period for 2 or 3 days my peace was lost but i am continuing my meditation still. I try to be detached from the results of meditation but the peace was so good, i am searching it now. Did anyone felt this kind of experience ? Any suggestions for me or encouragement to continue on the path ?