Incomplete evacuation, straining, gas build up, sudden abdominal pains, frequent urge to urinate, bloating, headache, fatigue, loss of libido?could it be ibs?

Maybe / maybe not: Ibs is a diagnosis of exclusion. The keys to your answer: do symptoms change, duration of distress, ; recent evaluation? Do you awakening from sleep due to pain, are your symptoms not intermittent but ever present or actually worsening, have bleeding/fever--if so then it is unlikely you just have ibs. In such a case, further evaluation is warranted to identify the correct diagnosis ; treatment.