Hi Anne
As part of informed consent you should be given all of the options available to you and talked through the pros of cons of each. This should include general anaesthetic. This will help you to make an informed decision that feels right for you. You could ask to speak to your GP about this and it is worth mentioning your previous experience in relation to pain.
You can also request to have a chaperone with you for the procedure which may help you feel supported. If you are awake for the procedure, speak to the staff performing the procedure about how they will check in with you to make sure they obtain continued consent throughout and that you are happy for them to continue.
Talk to them about your previous experiences and the importance of being able to pause or stop the procedure if you do need to. Some people have found it useful to have someone there with them to drive them home afterwards too, even if this hasn't been highlighted as a necessity in any of the info given to you beforehand.
I am so sorry you have had a difficult experience previously and did not feel you had been informed of what what going to take place. That is not in line with informed consent and should not have happened to you.