Can I be pregnant?

Julia
My current cycle day is 9, it's not very regular because it varies from 25 to 31 days. The last ones were 26, 30, 28. I had sex on my 5th day of the cycle - it was penultimate day of my period and we used the withdrawal method. On Monday (7th day of the cycle) the gynecologist I went to said that it's too late for Plan B and besides she thinks there's a low chance of pregnancy. However, I'm experiencing stomach ache, cramps, occasional dizziness, I can't eat. I'm a very emotional person and this is a very stressful situation for me, I don't think I'm coping very well with this.
Please refrain from lecturing me about better protection - I am very well aware of it. This situation was a mistake and I don't want to pay for it for the next 18 years ar least.