Hi nothing2lose. Welcome to BB and Happy birthday too!
You have certainly got a lot to take in and you are looking for a lot of information. I hope the members here can jump in and help you.

I hate to say it but get used to having a whole lot of blood tests done! Relatively painless, and they may offer some clues to the Drs about what course to take.
Your ultrasound with dye is a very common procedure. If a blockage is found it could be a nice quick 'answer' to your infertility. You'll find many people here have had them.
Bloodtests and sperm samples for your partner is vital. Infertility is often a combination of reduced fertility in both partners. Not just testing for STIs but all sorts of fertility related factors.
I am not sure about the laparoscopy risks in your case (weight?). It is the only definitive way of diagnosing endometriosis, but you should do all the less invasive tests first.
There is a chat thread for women who take Metformin and or Clomid (Serophene) here.
There is also a chat thread for women who are older and TTC (Trying to conceive) here.
Here is a link to the main chat thread for members who are LTTTC (Long Term TTC) with the help of AC (assisted conception i.e. IVF) here.
I hope you can find lots of information and advice/support in your journey to become a parent.

Best wishes
Jo