Could I be 3 months pregnant?

About 7 weeks ago I was feeling a bit different, my stomach seemed to be quite bloated, and I had a few other symptoms which I can't exactly remember now but I looked them up online and they seemed to similar to pregnancy symptoms at 4-5 weeks pregnant, I was really worried and took 3 pregnancy tests, all cheaper rather than brand names and they came back negative.

after that I calmed down a bit, I'm on the pill and have still been getting a withdrawal bleed every month, however they have been all over the place, last months it started two days early, this month gone it started three days late, and i recently read you can still get a withdrawal bleed even if you're pregnant.

So any way as time past my stomach started to change, I was thinking maybe it was me getting fatter (I'm a little bit podge as it is) what was happening was that the area generally above my belly button area seemed to be getting larger, as well as the (roll) underneath the belly button.

I never really have had morning sickness, although I've woken up and felt a bit queasy some mornings, and I noticed blue veins on my breasts being more prominent but again I know that the pill can do that, other than that I have not had many signs, then yesterday morning I woke up and the area above my pubic hair line was rock hard which completely took me off guard, I thought it must be my bladder, went to the loo but it was still there, it was there all day and is still here this morning, I looked up my symptoms online and could find nothing about bladders, but instead women talking about their uteruses moving up, they talked about a ridge, which I looked for, which I THINK I can feel but I'm not 100%, what's more, they said this happens from 12 to 14 weeks and I think if I was pregnant I would be about 13 weeks.

But yesterday I took another pregnancy test, again drugstore brand and it came up negative, and I took another this morning which was also negative. What does this mean, I'd not know what I should do, any similar experiences or guidance would be appreciated!