Hookup is pregnant

I’m a dude using my sisters account she said this would be a good place to ask for advice or unbiased opinions. I was chatting to this girl for about a month, we were going down the dating route at first but i don’t want that now so i told her I’m not into a relationship anymore and wanted fwb, she agreed with me, then told me a few weeks ago she couldn’t do it and wanted to be more than friends because she was catching feelings for me, told her I don’t want a relationship but the sex is really good so I’d love to keep doing that, or if it’s easier on her we could just stop talking cause we can’t be friends if she has feelings so anyway we hooked up again after she told me about her feelings and my phone went it was a tinder notification and she left pretty fast after it and text me later saying she can’t do this, that it broke her heart doing that when she knows there’s no connection at all, I told her she knew I didn’t want a relationship but she didn’t want to talk to me; she said we agreed if we were fwb we wouldn’t date or hookup with others so I said we’re both single there’s no harm so that was that, I text her a few days later about half 12am and asked if she wanted to come over; she blocked me instantly. Didn’t hear from her after that, until now 6 weeks later she text saying we need to talk, I told her I’m not interested and she kept insisting so I let her phone me for 5 and she told me she’s pregnant and it’s mine, I’m the only one she’s been with and we didn’t use protection, but I know it’s not mine. I grew up with 4 sisters and know how the cycle works, I spoke to them about it and based on her last period when she couldn’t hookup she couldn’t of been ovulating when we had sex so it’s not mine, I told her she’s obviously not being honest with herself and she needs to leave me alone, she suggested a DNA when it’s here and to get child support but I’m not doing it it’s not my kid. So what should I do?

After posting this I asked her for proof and she sent me a test and an early ultrasound she had done at the hospital last week she is 7 weeks, I know the dates could mean it’s near the same time but I know that she can’t be pregnant with my kid, she had her period less than a week before we had sex so she can’t be, my sisters have all agreed you can’t get pregnant that fast and I have 7 nieces so they know better than randomers thanks. She got the early scan cause she said she’s got something called endometris that makes her high risk this kid isn’t mine, that doesn’t make sense so stop coming at me for it, she’s clearly trying to con me and she refused to get the dna before the baby is here because it has a risk of miscarriage