Strange period or something else?

Hey there, I wonder if anybody could help.

I was diagnosed with endo about 3 years ago.

My partner and I have been trying to have a baby for around 6 years. About 6 months ago I had an internal ultrasound and the nurse said my right ovary looked very close to my uterus but I haven't heard anything about it since. Fast forward to my last period which was on 13th November and was a painful but normal period. On the 28th November I had some orangey pink spotting (I've never bled in between periods before) it only lasted a couple of hours. Today my period is now a week late, I'm usually pretty regular. I took a pregnancy test last night and one again first thing this morning and both were negative. I honestly didn't expect a positive result anyway. Since they've been late ive had a really sore back, especially when out and about, ive been tired constantly and I've also been feeling sick, been having hot flushes and cramp when active although these could be normal period symptoms for me. Just wondering if anybody has experienced anything similar? I think it must just be my endo messing about with my insides however I don't think I'll manage to get a doctors appointment before Christmas now. I also usually get really emotional during my period and for the last few days I've been really snappy and angry for the silliest of reasons.