How does it feel having contractions???

anyone who can tell me how does it feel having contractions? I have a lil girl but she was preemie 31 weeks and I didn't feel any contractions and I was at 6 of dilatation, luckily I had an appointment and they send me to ER so I get c section... now with my second baby they give me Progesterone but right now idk if is contractions or my mind is playing with me since I don't know that feels... can someone help me? I'm 25 weeks pregnant...