Vibrations in my body

I'm male, 29 years old and have recently started to experience the following symptoms:

Starting about 1 month ago, I have noticed a strange inner vibrating feeling, usually after waking up but not every morning. So far I have noticed it about 4-5 times. I have also noticed it once prior to going to sleep after lying down. It only occurs when I'm lying down on my bed and usually subsides after a few minutes and taking a few deep breaths or soon after standing up. There is no visible vibration or shaking; it feels like it is happening throughout my body, particularly in my arms, legs and chest, but never my head or neck so far.

This is all very confusing because in addition to this, since about 6 weeks I have had this feeling that whenever I try to empty my bowels in the late afternoon or evening, I am completely unable to do so and I get gas, some cramping and a sensation that there is a lot going on in my stomach when I try to go to sleep. In the morning, I am able to have a normal bowel movement which is usually followed by 1-2 more bowel movements within a couple of hours of the first bowel movement.

I guess I've become a bit of a hypocondriac in recent times since a caffeine overdose on July 10th caused an unusually long period of tachycardia and feelings of intense anxiety (which only exacerbated my symptoms). After a visit to my GP and the cardiologist, it was determined that I have no heart problems and any accelerated pulse rate is only due to anxiety. Lately I have reduced my stress and since I am waiting for my new job to begin mid-October, I haven't been working since late July when I had to finish my work contract early due to my caffeine overdose incident. This means I haven't had much stress in my life recently, but I have also spent most of my time on the couch watching TV or surfing the web, doing very little exercise and only going out of the house to run errands 3-4 times a week.

My blood work also checks out and I have been tested for thyroid problems (I don't have any); diabetes, electrolyte imbalances, high cholesterol levels etc. none of which I have. In fact, my diet is quite good; I eat salad about 5-6 times a week and my diet is rich in fruits and vegetables although I do also indulge in cheese and other processed foods. I have completely cut out caffeine from my diet meaning I currently no longer drink coffee, any type of caffeinated tea or chocolate. Also, I don't smoke and only rarely consume alcohol.

Am I worrying too much or is there a basis for the vibrations I am feeling and could they be related to some kind of bowel problem so far undiagnosed?

Thanks for all your help.