Confused

Our doctor told us the 2nd trimester starts at the beginning of 12 weeks. I thought that was early and that it should be the beginning of 14 weeks. I just called to schedule our 1st trimester screenings and that lady was saying beginning of 14 weeks. You would think the 2nd trimester would be the same for everyone. I just don't understand how I am being told two different things, which are off by TWO WEEKS! That's a big difference. Iv just been kind of disappointment with my doctor(s) they didn't even tell me what they check for when they take my blood or urine, I should have asked I guess, but I just feel like I'm left to figure out everything on my own. I felt like that when I had my miscarriage too. The only thing they told me was if I was bleeding a lot to go to the ER. How is that all you tell someone? I google everything and ask others that have been pregnant with all my questions. And when I brought a list of questions to the doctor after my miscarriage he looked at me like ok, why are you asking me these questions. Maybe we should try an appointment at a different location, but I think it might be the same doctors. I am pretty sure I want a doula when labor gets closer. Insurance doesn't cover that so of course Brent is going to say you don't need that, but I do. I always have so many questions and doctors just don't care. I freak out about everything and I was someone that will be there to support me. I know I have friends, and they have been amazing, but I think a doula is still going to be in our future. 

Update: I called to reschedule our appointment with the first doctor we saw before we were even pregnant, and now the doctors office has no record of me! What is going on?