How do I proceed with on the job injury?

I "strained" my back while positioning a patient, on Jan 14, 2014. I called my supervisor and left her a message, saying I pulled, strained or sprain my back an hour or so later. I called in 15 and 17th due to back pain. The 16th was a scheduled day off. It was several days later that I mentioned it to my supervisor. She told me she didn't hear the message. She was on a few days of vacation beginning on the 14th. That she would let the employee health nurse know as there was paperwork that had to be completed. On Jan 29 I was in the office, the employee health nurse walked over to me. She said, "A little Birdie told me you hurt your back, but you're feeling better. Do you need to see a doctor?" She then walked away without getting my answer. My back has been hurting off and on since, but getting worse when it hurts. I again called in on Feb. 17 and 19th sending an email to my supervisor, that my back was hurting and I needed to let it rest. 18th was a scheduled day off. On Feb. 20, 2014 there was a reduction in force at my work and I was laid off. I was never given any paperwork or really offered medical attention. I don't have anything in writing, other than my comment in payroll website. That my absence on Jan 15th was due to, "back strain from patient the previous day." Which my supervisor manually approves each daily entry. Is it too late to get medical attention?