Good morning, do you not feel you have had your answers with all your exams and bloods coming back normal? My only advice would be your own biggest health advocate if you feel something is not right, but I’ll be honest - reading your story does sound like you have had good health care and lots of tests so I wonder if speaking to a GP about the actual anxiety might be more helpful than more tests. 
I think night sweats and unexplained weight loss are symptoms that my GP says to look out for when I was having period problems. For myself it turns out to be a very large cyst in my pelvis. I was told I had a mass in October and what it was in January. Nothing moves quick so get a smear test booked in when you can so this anxiety doesn’t affect you for further months. 
Good luck - try and stay off google. I have wasted MONTHS of my life that I won’t get back, I think if my mass had been cancerous I would have been livid with myself for spending so much time worrying. 
the best advice I got was to set aside 1 hour per day to worry, to google, to panic and do whatever you need, then put it all away and not allowed to look again until the next day. At least it lets you have some form of normality if you just can’t stay off it. 
Good luck x 

I forgot to mention I had scans not actual examinations, no cysts were found and ovaries looked healthy on internal scan, I'm just so petrified to go back for a smear, I should be called back next month or the month after to have another one, I just know it's going to be bad news I can feel it! Before I had my smear I knew it was going to be bad and I was right, I just can't stop thinking the absolute worst I've had so many doctor and a&e visits now and they keep telling me I'm a "healthy" 29 year old, but why would I be having these pains and the irregular periods unless something was very wrong! I know googling is the worst thing to do but I don't have many people to talk to and it's the only thing I have.