I'd call your RE and ask for a local clinic to do the test. You totally don't have to go to the RE for a beta, it's just a blood draw. I found a local place that just does blood work and had my order faxed in. Very easy and much cheaper! (Quest is one that has offices everywhere, if you insurance takes them, Shield is another. BUT: Have your RE write STAT on the order, it can take a day or two to get results back.)
Anyway, I suggest RE since OBGYN's can be very slow (for us!) on these and want to wait a week or two after AF is late sometimes.
As far as temps: They are helpful and I loved using them but they are not the end all and be all... too many changing factors. (Like was a fan on, were you sleeping with your mouth open just before you woke... you know, all that!) So don't put all your trust in them.
And P4: For me sometimes it slowed down my AF, sometimes not. I know, not so helpful, right? Sorry!
Good luck and hang in there,