Positive to negative

Just over a week ago I took 3 tests over a few days 1 manual and 2 digital all positive but vvfl and digital 1-2 weeks. Come to today, found some tests in the cupboard thought I'd try again, I have had symptoms up to now as well, took a manual one but I didn't have a big enough sample so I couldn't be sure. Waited a while took a digital it took ages and then came back negative. Waited a little longer but anxiety got the better of me took another manual but the test was faulty no control line, this is the second one in the same box to do this. Do you think it is a bad box and I might still be pregnant or chemical pregnancy? Please help I'm so worried.