Where do you get the blue veins when pregnant?

i thought last month that i might have been pregnant and now i am ttc. but i cannot stop noticing that my breasts have been hurting for almost 2 months now since my last period which was 16th may i thought i may have been pregnant when my period was one day late and i got spotting that lasted two days on the 12th june. and now i have larger breasts with blue veins through them and on my stomach and on my legs. ive always had visible veins and i dont think im pregnant cause i had a blood test and two urine tests and all were negative so what could be the other causes for this