I'm a 25 year old female who weighs 135 and I'm 5'5
I've struggling with going to the bathroom for the past month. I usually have to sit on the toilet for 20 mins to an hour and sometimes I cannot even make a bowel movement. If I don't take copious amount of fiber and/or laxatives then I might not be able to go and be constipated for 4 or even 5 days before caving in and using a laxative.
I have no clue why I have such a horrible time. I exercise for an hour, sometimes 2, everyday with maybe a day off from exercising during the weekend to recover. I run a lot and do a lot of cardio. My diet mainly consist of fruits and veggies and I'll have meat usually with just one meal, and then I snack on granola bars or dry cereal (I can't have milk I'm lactose intolerant.)
I hate the fact that I'm struggling with this which causes be a lot of stress which on contributes to the problem. And I hate that I need to use laxatives most of the time, because I know that it can cause a lot of horrible problems in the long term, so that causes me a lot of worry.
I haven't been able to see a doctor since I just moved countries but i had this problem before years ago and the doctor performed a colonoscopy but it turned out to be healthy he said and that 'I just have a dysfunctional digestive system' and nothing else, no medical tips or nothing on how to maintain my digestive system.
Definitely need to be sure you're drinking enough water (2-3L per day). Dehydration is the #1 cause of constipation after diet and exercise in your age group. IBS is the next most likely for your presentation.
GentlePandoran has a lot of great advice, but please do not start eating 1200 calories per day. Your BMI is 22.5, and the normal range is 18-25. Your weight is perfect, and you exercise and eat very healthily as-is. You may doing a bit too much cardio... it's hard to tell.. try altering these things and seeing what works for you.