Pregnant?

I came off the pill in March and had came on in April, I haven't came on this month and should of come on by now, I tested Saturday (negative) but is there any chance I could still be pregnant? Missed period, very depressed to the point where I keep bursting out crying, period cramps, little spotting, tingly nipples and not bad but a bit tender boobs. I've heard before some women's pregnancys can't be detected on test I'm going to the doctors tomorrow to see what they will say but does anyone else think I have a good chance or I'm playing tricks on myself? Tia X