We are sorry to hear of the trauma that you’ve experienced and how it is affecting your needs at the mikveh.
Halacha calls for a halachically observant Jewish woman over the age of twelve to confirm that an immersing woman’s hair is fully submerged underwater.
If it would be helpful, you could ask a friend to accompany you and observe the immersion, rather than the official attendant.
Depending on the configuration of the mikveh, it may be possible for the attendant or friend to watch from outside the door of the mikveh room and just confirm that your hair is underwater.
If this is not currently workable for you, another option is to keep your hair short. When a woman has short hair that is surely submerged during immersion, she need not be supervised by an attendant.
Immersing alone with longer hair is more difficult to permit. In cases like this, it would be permissible to lightly gather your hair in a loose, water-permeable net or in your hand with a loose grip prior to immersion, keeping a very light grip underwater and shifting it to ensure that it’s all submerged and that water reaches all of the hair.
In Israel, mikva’ot are legally required to accommodate a woman’s request to immerse on her own. Elsewhere, mikveh policies vary. You should probably clarify this in advance with the mikveh, adding that you received a halachic ruling permitting you to immerse in this fashion.
Please let us know if we can be of further assistance. We hope and pray that you are able to recover in the near future.
Please see here for additional discussion of this topic.