Am I pregnant or just imagining things?

Hi ladies.  Hubby and I have been trying to conceive for about a year now but no luck.  This past week I've been feeling very odd. I've experienced nausea several times while riding in the car and also in response to the smell of dog food, ive had dull back pain, been very emotional, and have had a headache off and on for the past couple weeks. Last night I took a First Response test I already had and after about 30 seconds without seeing anything but the control line I tossed it out.  came back 30 minutes later and it had a faint pink line.  This morning I went to the chemist and bought another box of 3 First Response tests.  I took the in stream test and within about 30 seconds saw a faint positive line again so about 3 hours later I took the digital but it said no.  I did have  a bit of spotting last week when I thought I would be starting my period but never needed a tampon or anything.  I'm usually very regular.  What do you ladies think?