Hello and welcome to eHealth Forum!

No there is no chance that you are pregnant. The third day after your periods is usually absolutely safe time unless you have a very short cycle of 21 days (yours is 28 days so ovulation occurs on around 14th day) or you have a long period of 7-8 days. One cannot conceive by having unprotected sex during this time. So if you had a long period of 7 days and had sex on the third day ie 10th day of cycle, then also the chances of conception are less as if the ovulation occurred on 14th day, the ovum cannot live beyond 3 days usually.

If you took plan B within 72 hours, it will act. Also this can cause a delay in period due to hormonal changes. But you had periods on time. Even if you had a faint line for ovulation, you have ovulated.

You do not appear to be pregnant as you had periods, positive ovulation line and negative urine and blood pregnancy test. Hope this helps. Take care!