I keep getting negative tests, but I'm sure I'm pregnant?

Well my last real period started on the 14th April, I then started light bleeding around the 5th of May which is totally unusual for me, I have never once had my period early and it was just brown blood. I then started to get extremely tired, having to take naps every day. I then started to get headaches everyday which is another thing I rarely suffer from. I went out for an evening with a friend and had one drink and it made me feel extremely sick. I then started to get a lot of pregnancy symptoms, very sore/tender / (also noticed montgomery tuburcles had started to appear, also very prominent blue veins) I also have prominent veins all over my body. I can feel my heart beat thrugh out my entire body and at resting it is at 96 beats per minute. I started to break out in spots very badly and my skin become very sensitive to my cleansing routine although I haven't changed anything in years. I have been so dehydrated, I can't stop drinking and have been getting up 5 to 6 times every night to go to the bathroom. I'm a vegetarian and I have been craving meat, especially pork scratchings, I also can't do washing without sniffing the washing powder for about ten minutes. My hair has got very dry and unmanageable. My dog is acting really weird around me (usually jumps up at me but now just rests her paws on my belly.) I was getting cramps like period cramps for about two weeks but no period, last Sunday 5th June, I woke up at 7am in pain, I went to the bathroom, wiped and there was blood so I thought I'd started my period, I then tried to go back to sleep but found my self in extreme pain (cramping like I'd never had before) I thought I might be having a miscarriage. I took some pain killers and fell back to sleep for a couple of hours, when I woke up I felt fine. Went to the bathroom and there was no blood in my knickers, I wiped and there was blood, this continued for the day until about 6pm and the bleeding stopped completely. I have taken about ten pregnancy tests starting the 23rd of May and they've all been negative. I just feel different. I can't do my trousers up anymore and some days I am so bloated, I've never had this before. Today I went to the bathroom and there was a tiny bit of brown blood. I have a doctor's appointment tomorrow. So hopefully I'll find out then. What do you think? Sorry this is so long.