Why are my periods intentionally trying to mess with my head?

Hi, first time poster here so sorry if this is long and a rant

Where do I start I feel so down at the moment and that my periods are having a great laugh behind my back. 
A bit of background to my story, I always had regular periods like clock work almost always came on 28th day for 15 years until January. My mum passed away in January so when my period was a day late in February I wasnt too concerned. However this continued in March then in April it was 3 days and May and June 4 days. Now this month it has been 5 days, however as with a few of the previous months when I have went to buy a pregnancy test my period has came. I bought one this morning 4 hours later when I went to use it what do you know there is little spots of blood on the toilet roll. 

I am getting so down now with it all as I am getting on at a bit at 29 and would love nothing more than a child but I feel my cycle is intentionally trying to get my hopes up (stupid i know) 

I have also had a lot more different symptoms the last few weeks whch got my hopes up, like vivid dreams, weird dreams I almost never get, extremly tired the last few days (I dont really get this before I am due or maybe just dont notice it) and have have constant diorhea from around 28th july. 

Anyone have any advice to get me out this hole so I dont get depressed I really dont want to end up being one of those that just gives up hope but I dont think I will be buying any more tests until I dont have my periods for a few months in future