Possibly pregnant ? help!

Maddii
Okay so this is super complicated to explain but basically I had to go off the pill for 2-3 weeks because I was getting a lump in my breast checked (everything was fine) but I then had to go back on the pill and the first two weeks of going back on it I had sex with my partner almost everyday and about 70% he came inside. 
I was supposed to have my "Girlies" about a week ago but because of the whole going back on the pill it's bounced them back to about next week, so I haven't had a missed period as of yet but I've been feeling a bit weird... 
I've been feeling nauseous a lot but not actually been sick.
I've been getting very random headaches and dizziness out of nowhere. 
Bit of bloating and sorry for the grossness but pretty constipated too.
I just read something about waiting two weeks before having unprotected sex because it takes a while for it to work. ( I never knew this as for the huge mistakes appointed above) so that's why I'm conserved !! 
Anyone experienced this or can help?