There are many reasons why victims of rape, sexual assaults, sexual abuses, and sexual coercion don't feel they expressed their opposition "enough". We could be confused about our feelings, scared, shocked and not able to think quickly, not very assertive, and being manipulated. It is not unusual.

Being there and not running away are not consent. If you aren't willingly planning to do it and/or excited about it, it isn't consent. "Allowing" it, not fighting "hard enough" to get away, and being in a certain situation are not consent. You said what you wanted or didn't want, and he didn't respect it.

We can change our minds at any time, and we can be confused and need more time. If the person doesn't allow us these things, they're in the wrong, because a sexual encounter should be enjoyed by both people and if they don't care whether we are enjoying it or not, that's scary.