On Monday night, I took two First Response pregnancy tests. Within about a minute each time both lines showed up. Each of them were distinct, but they were both fairly faint.

I went to a pregnancy center on Thursday, and took another urine test, but this one was negative.

Now, on Friday, I have started a heavy flow with cramping and nausea. Do you think I am pregnant or that somehow I just had two false positives?

Yes, false readings are ALWAYS possible.

It may also have been an early loss. Sometimes a woman will get a positive, only to have it become negative a bit later due to an impending miscarriage.

Was this the time you would normally expect your period? If you followed the directions carefully on the pregnancy tests, a false positive is not common. If you are unsure, give it another week or so and try another test. Some women do have bleeding in early pregnancy which can sometimes obviously be due to a miscarriage, but not always.

If you feel the bleeding and cramping are excessive for a regular period, consult your doctor. If it were due to a miscarriage, best to have a follow-up check.

First of course the best time to test if first thing in the morning with the first urine. But yes false readings are very possible. Esp if taken within min of each other. If in doubt or concerned, a visit to your doctor could be called for