HELP!

So I got 2 positive hpt 13 and 14 of June. But 15 and 16 I spotted and it was off and on not heavy like a period. But Thursday the 29th of June I got a faint line again on hpt that I could clearly make out. I had a blood test done the 15 and it was negative but they told me I could test again if I wanted too. Any thoughts on what is happening. I've had cramping this week but nothing major.. and my next period is supposed to start next week. I'm confused.