Many things can delay a period - stress, hormone imbalance, infection, illness, STD, change in weight or diet to name a few. Also, many things can also cause the symptoms you describe, so you can't really rely on these for determining pregnancy. All you can do now is wait and see what the results of the blood test is.
It does sound as tho u could b pregnant but it could also b pms but if u don't usualy get any the symtoms then chances r u could b having a baby :-)? The tests do usualy say wait til ur l8 but some detect as early as 5 day b4 u r due but the blood test should tell u for sure so y can stop worryin but good luck and I would like if u could let me no wot happens plz?? X