What does your lease say about this? It would discuss what would happen in the event of a holdover or a tenancy by sufference. usually when a tenant overstays the term of the lease it turns into a tenancy at sufference, which is usually a month to month term (unless the initial term was measured in week to week or day to day).
Whether or not she evicted you is not the issue.
since you overstayed you may be liable for the rent for the month, unless your lease says differently. If your landlord gets another tenant in before the next 30 days are up, you may get a portion of this back.
You may want to look towards the Neighborhood Justice Center, as an attorney can help you with this, it may cost more than the rent for the month.
Hiring a lawyer will not be of worth to you, because the fee you have to pay him/her will likely be the amount in controversy. Anyway, if the lease does not say otherwise, your tenancy becomes a month-to-month tenancy after the expiration of the lease. As such you have to give a 30-day notice to your landlord that you will be vacating the property. If you don't, then she will be entitled for the next month's rent. Again, check what your lease addresses this issue.