WALKING DEAD 24, the title you chose for yourself (especially if you're 24) is OMINOUS. Please change your lifestyle.
You can be skinny and still be really unhealthy. It will cause you problems if you have a sedentary lifestyle no matter how old you are.
http://www.hopkinsmedicine.org/healthlibrary/conditions/cardiovascular_diseases/risks_of_physical_inactivity_85,p00218/
There's many other links on the subject you could check out, It is big business these days, with all sorts of people young and old getting heart disease etc just because they refuse to get off the couch. It's real easy what with computers and 50" screens , to be sedentary. You really need to make some changes for yourself.
Also, constipation is often the case with people who don't get enough exercise, so here's a link to talk about what exercises will help you to obtain a proper bowel movement.
http://www.webmd.com/digestive-disorders/exercise-curing-constipation-via-movement
And yes, i also think you need to deal with these symptoms with your doctor, and take his advice. If they don't know that you are sedentary or don't ask you outright, you need to tell them and ask if it might be related.
Many doctors go through their career benefiting from people that get sick from lack of exercise. In fact, doctors usually always treat pre diabetes or diabetes with medication instead of expressing to their clients that it would be much better for them to deal with diabetes through diet and exercise.
So, you have to take your health into your own hands now, and do everything you can to save yourself from the diseases that you will get if you continue on doing nothing good for yourself.
You're in my thoughts and prayers. Please TAKE ACTION, It can be a lot of fun. Why not get yourself a bike (even used) this summer and get out there? Do you have any friends or a husband or kids , that would like to go too? There's so much more to life, than just sitting around. You'll regret not getting active, when you're sick. And if you're lucky enough to get old, you'll regret not having the memories associated with an active lifestyle.
So, be good to yourself, please, and make a plan, and stick to it.
Sometimes your BM can trigger Vagus Nerve problems, and these problems can have symptoms like what you are describing. Check with your doctor, only he can diagnose this for you.