In sure you enjoyed having the sex without a condom and clearly did not mind the risk of STIs from this woman .
You shouldn’t have trusted her , you should’ve used a condom too . So yes you could be Angry with her but you need to be equally angry with yourself for not considering that her contraception may fail ,and taking additional precautions given you strongly did not want another child .
At the same time you do have my sympathy as it can be a bit of a shock to know you are pregnant when you have been taking precautions. Don’t do or say anything rash and just try to calm down for a bit because your anger isn’t going to change anything and you need to be constructive.
If you do not intend to continue being with this woman you need to tell her categorically that you do not intend to pursue a relationship with her , so she understands that you do not wish to be involved with her . As far as the child goes whether you want to accept it or not , you are the father and have responsibilities toward the child .
I don’t underestimate that this surprise pregnancy is really stressful , counselling may help ?
If this makes you feel bad please bear in mind that many many many women becoming pregnant unexpectedlydespite using contraception,I know this is different , but also the same because you are unexpectedly expecting to be a father.
The point is that many women who are in the situation you are , eg those already in marriages or long term relationships ( and those who aren’t ) HAVE to come to terms mentally and emotionally and often take the physical hit for a year , changing their lives , because they are the ones carrying that child . That’s what this woman you have slept with is doing .
You need to simply accept the mental and emotional hit , physically , nothing affects you , you aren’t going to give birth , your body will remain the same , and you can choose to have no contact with the child.
Women in your situation who continue the pregnancy quite often don’t have that privilege .