Anxiety & depression. Hell to haven!

I am a civil engineer, i realized that i am unable to sleep at night. When i am sleeping a lots of tension which is not clear to me that what tension is this, is running on my brain whole night. When i wake up from sleep at morning i realized that i sleep only physically, my brain wont sleep, its on duty 24×7. I also feel Anxiety and afraid from all matters, thinking about hell to haven regarding on each and every small matters. Also suffering from depression and unnecessary fears. Loosing the memory and concentration power on both of my work and study. From when i feel this problem i also started frequent urination. Wake up from sleep at night 2 times. Please suggest the solution regarding the same, and suggest me which specialist dr should i have to visit. Please help me.