poly ovaries

Naomi
Right so I have polocystic ovaries, so my periods are quite irregular.
It's now been 19 days since I should of started my period. My last period started on the 16th March and lasted 6 days which is normal for me <-- that's actually one of the only normal things about my period. I get ridiciculous cramps like the first day of my period which make me bed ridden. It's horrendous trying to work!
I have taken a pregnancy test) which I took very late in the evening) and negative, I've had no signs of pregnancy apart from putting on a bit of weight, but I put that down to not training last month.. 
I am fed up of constantly waisting money on buying pregnancy test for negative results. I've been to the doctors and there magical plan is to put me back on the injection contraception. Which one, me and my partner don't want contraception as if I fell pregnant we would be happy, if not then it doesn't matter.. but we have been having unprotected sex for years now and nothing, I don't like the feeling of having to wait for my body to sort itself out so I could potentially fall pregnant years later. Plus I never had any issues with my period tills I was on the injection for a good few years!
I do have quite a stressful life as I have a demanding job and I have recently forced myself to try get back to the old me and fit as a fiddle again, all of which can take a toll on your period.. but surely not to this extent. 
I just don't even know what to do, I'm blatantly not pregnant, no symptoms, my periods are a mess and that stresses me out :(
Feels good to rant! Anyone else have the same issue!