Well. Let's start with some of the basics.
You are wanting to hold an emergency medical technicXXXXX XXXXXable for an improper emergency diagnosis. You signed a waiver to not have them take you to the hospital in the ambulance based on your belief that their diagnosis was probably correct.
However, an emergency medical technician is not a doctor and cannot be held liable for medical malpractice in the same way that a doctor can who misdiagnosis you.
The law in Texas provides the following:
Sec. 74.151. LIABILITY FOR EMERGENCY CARE. (a) A person who in good faith administers emergency care is not liable in civil damages for an act performed during the emergency unless the act is wilfully or wantonly negligent, including a person who:
(1) administers emergency care using an automated external defibrillator; or
(2) administers emergency care as a volunteer who is a first responder as the term is defined under Section 421.095, Government Code.
(b) This section does not apply to care administered:
(1) for or in expectation of remuneration, provided that being legally entitled to receive remuneration for the emergency care rendered shall not determine whether or not the care was administered for or in anticipation of remuneration; or
(2) by a person who was at the scene of the emergency because he or a person he represents as an agent was soliciting business or seeking to perform a service for remuneration.
(c), (d) Deleted by Acts 2003, 78th Leg., ch. 204, Sec. 10.01.
(e) This section does not apply to a person whose negligent act or omission was a producing cause of the emergency for which care is being administered.
Acts 1985, 69th Leg., ch. 959, Sec. 1, eff. Sept. 1, 1985. Amended by Acts 1993, 73rd Leg., ch. 960, Sec. 1, eff. Aug. 30, 1993; Acts 1999, 76th Leg., ch. 679, Sec. 2, eff. Sept. 1, 1999. Renumbered from Sec. 74.001 and amended by Acts 2003, 78th Leg., ch. 204, Sec. 10.01, eff. Sept. 1, 2003.
Acts 2007, 80th Leg., R.S., Ch. 705, Sec. 1, eff. June 15, 2007.
Sec. 74.152. UNLICENSED MEDICAL PERSONNEL. Persons not licensed or certified in the healing arts who in good faith administer emergency care as emergency medical service personnel are not liable in civil damages for an act performed in administering the care unless the act is wilfully or wantonly negligent. This section applies without regard to whether the care is provided for or in expectation of remuneration.
So the first question in your case would be whether the EMT's actions were willfully or wantonly negligent. They did not refuse to take you, they simply recommended that you not go. So, this likely does not rise to the level of willful or wanton negligence
(i.e., gross negligence).
Second, assuming you get over the above-stated liability hurdle, you then have to show causation. You say the medical evidence shows that had you caught the condition sooner you would have had a different result. Nevertheless, you will have to have a solid medical opinion supported by medical expert testimony which states but for the fact that you were not taken to the hospital 2 hours sooner, you would not have to have the surgeries. I make no judgments here because I'm not a doctor and I have no idea what your medical records state, or what the medical evidence you are referring to actually shows. However, I can imagine that there is going to be a doctor on the other side who can disagree with you on this, and a 2 hour gap would make me worry about the strength of your claim if I was your lawyer.