I'm kind of curious as to the reasons they told you that you were let go, but I guess you didn't share them for a reason.
I worked as an extern at a local hospital during my last semester of school and had two RN position offers before I even graduated. I opted for one on a surgical floor and am still there today. I have never felt at all discriminated against by coworkers or patients (aside from the occasional patient that prefers female help for baths and what not), and have never felt like I had to work "10x harder" than the female RN's I work with.
It would actually be kind of a good thing if your gender was the only reason they fired you, because that means that there are many other facilities out there that would be thrilled to hire males on their nursing staff.
So it could have been discrimination, but I'm willing to bet that if they hired you as a male nurse then your gender probably had very little, if anything at all, to do with your firing. I would start to evaluate other reasons they might have had to let you go. If they didn't give you specific reasons, then diplomatically go back and ask them, explaining that you want to better yourself so that you don't face the same situation in the future. For one thing, wherever you apply to next is going to want to know why you were let go. Keep in mind that good bedside manner is only a part of the job. Just because your patients love you doesn't mean you don't have other equally important areas of the job that you may be weak in.
Also, were you not still working with a preceptor? Our floor usually trains for a few weeks before letting us "fly solo". If so, then your preceptor likely had something to do with it. In which case again, go and try to find out what specific areas you can improve to avoid the problem in the future.
If they can't give you a straight answer, then it is possible there were some personal, unprofessional reasons you were let go. If this is the case, and you know that you're efficient at all of the many tasks that make up the nursing job, then keep your head high and get your applications out there. Remember, interviews are more important than anything else in the hiring process. Go in confidently and professionally, and explain why you feel the last job didn't work out and why you can do this job better.
Regardless of you financial capabilities, I really doubt medical school is the solution to this problem. Dig deep, find the real problem, quit blaming it on your gender, and move forward.