Contractions

I'm 4 months pregnant and last night was so hard for me. I started the day before when I sleep on my right side I would feeling this pain which I have never experienced before. Then in the morning I went to work then that pain started when I was knocking off. The I managed to arrive home. The pain started being worse... It was like this baby is turning and my stomach then grow and become hard. It took 1 to 2 minutes....but it felt like 10 minutes. It happened few times. Eventually I sleep. This morning I'm having miner cramps and at some point that pain does attach me. Should I be worried. Help