How to tell the difference between bowel obstruction and constipation?

A week ago I started taking pills (irrelevant to what) that has rare side effects of bowel obstruction and constipation. Three days after I started with the pills I started having constipations. That was four days ago. At the first two days I didn't make much of it because I've forgotten the side effects buy yesterday I looked them up and found the above side effects and I stopped taking the pills (that what it said to do if one of those side effects occur). It also said to go to the doctor but my mom is too damn positive that it just constipation but I'm not so sure. As I said I've been having constipations for 4 days in which I managed to poo twice, but both weren't full (they ended with constipations). So I looked up online about bowel obstruction and I don't know what to make of it. At small cases it said there'd be vomitting so I was relieved because I didn't vomit but then it said that in severe cases there might not be comitting :( I've been having stomach pains too. What to do help =[