I wouldn't be concerned about it. Many of the guys I've known in the past have had some very "pretty" handwriting with big, rounded letters and the like, just as I've known plenty of girls who made sloppy, angular letters. I've yet to see anyone actually bother to question it. Especially when it's an issue of your physical comfort, it should not raise any issues--and heck, if it did and I were in your shoes I'd go off on a rant about how handwriting doesn't have a gender say I have to write in a way that's comfortable for me and that's that.
That's not to say that I haven't wondered about my own handwriting being perceived as "too feminine" from time to time in the past, but then I realized that A, nobody else was going to care and B, different people write in different ways regardless of gender. Oh, and C, I like my handwriting how it is anyway. ;B