Cramping and nausea while using the bathroom?

Since Sunday I have not been feeling good....I've been fatigued bloated had heartburn gas and felt nauseated. I'm usually regular but since I haven't felt good its been difficult to go. I would cramp up real bad run to the bathrom and not much happens. I wake up today and I'm gtting real cramped up so I run to the bahroom and this time I go. Its thin longer stools and everytime it starts to go I get s sick and feel like I'm going to throw up. What could be going on? I've been reading about bowel obstruction and I'm scared I might have that. I've never had sugery or anything but in the past I've had trouble with gerd ibs and haviing a really bloated up stomach. Hopefully I can get some insight on this. Thank you.