I recently answered a question asking about signs of diabetes:
Some of your symptoms fit with the possibility that you have diabetes: the extreme thirst for sure! The symptom you describe as visiting the toilet might fit, if you mean "frequent urination with large volumes of urine," which is what people with uncontrolled diabetes have. Weakness also fits with diabetes; it's common that people with uncontrolled diabetes have a feeling of extreme tiredness or fatigue. I don't associate irregular heartbeat with diabetes.
Folks with undiagnosed diabetes may have symptoms such as excessive thirst and excessive urination (especially at night, which is called nocturia), and may have uncontrolled hunger and sometimes they paradoxically lose weight. Fatigue, change in vision, increased likelihood of infection, wounds that won't heal, irritability, and numb sensation in hands and feet are also on the list of diabetes symptoms.
It is important to understand that not everyone will have every symptom. In fact, diabetes sometimes is diagnosed without any symptoms at all. And sometimes patients have typical symptoms of diabetes and don't realize that they have anything wrong. Personal story: when I was first diagnosed, I had fatigue (which I blamed on workload from my job), blurred vision (which I assumed was due to change in my refraction due to aging), and nocturia (which I thought was due to enlarging prostate).
Since you realize that you are not feeling well, it's time for a checkup. Because of the possibility of diabetes, be sure that you get a blood sugar test, and probably also get a lab test called A1C or hemoglobin A1C. However, I don't know what to make of your symptom of irregular heartbeat, and you should discuss it with your physician as probably being a separate problem.
BTW, you'll notice I talk about "symptoms" when you used the word "sign." The two words are frequently used together, "signs and symptoms." In commonly-used medical jargon, a symptom is something noticed by the patient (such as thirst), and a sign is something observed by the physician (such as an abnormal lab test like high blood sugar level). No big deal; just us docs using our jargon...
Hope this helps!