Looking for some help...

sorry for the long story but I was hoping someone had been through this before. I just found out today that I'm pregnant and I'm super excited. What I'm worrying about is that I don't have short term disability with my job that would pay me 60% of my salary when on maternity leave. (I'm in the US and I don't get paid maternity unless I have this, they only hold my job for 3 months.) If I signed up for it in November when enrollment happens it would not take effect till January. And I couldn't go to the doctor until then to have them confirm pregnancy because then it would be preexisting to the coverage. I guess my question is how long can you wait before having your initial screen?