Brief Answer:
Could be, but I would still recommend a repeat testing in a months time

Detailed Answer:
Hello ma'am and welcome.

Thank you for writing to us.

I have gone through your query with diligence and would like you to know that I am here to help. I would just like to first mention that chlamydia is a bacterial infection which if left untreated can result in an array of complications that can range from simple to as serious as infertility. So I am not sure what made you leave it untreated, but if you do return a positive result anytime (through laboratory testing), then please take the course of antibiotics.

A negative result can mean the infection was taken care of by your immune system, but it can also be a false-negative which can be influenced by various factors. So I would recommend a repeat test to be conducted in a months time (by an experienced technician and a well reputed diagnostic centre), and if that also returns a negative result then you can rest assured ma'am.

I hope you find my response helpful. Please feel free to write back to me for any further clarifications, I am always here to help.

Best wishes.

---