It's so hard to say because there are so many aches and pains associated w/ being pregnant. If you are in doubt, it is best to be seen. There are instances where women are in labor and don't even know it. I wish I could be so lucky!!
Anyway, I would take some Tylenol and maybe take a warm bath. Try to keep your feet up and see if this helps. If you start contracting, def go in. Oh, you can also use a heating pad for your lower back pain.
I hope you feel better soon!
Sounds like you could have a yeast infection and I also have the same pains going on and my doc said it is from everything getting bigger and resituated. He said it doesn't natter if its your first or second or third because everything still has to move all over again