Is it unmanly to cry?

There is nothing wrong with crying, regardless of your gender. The idea of it being "unmanly" is just a ridiculous stereotype based on archaic, gender ideals which no longer have any relevancy. Crying in public does not make you weak or any less of a man. It makes you more of a better person than the people who insult and pick on others, such as the kids at your school. I know it would be hard to ignore their comments (especially given the circumstances), but it's the best thing you can do. Bullies crave attention and if they know that you are paying attention to what they are saying, they are only likely to continue doing it. 

It's important to remember that there are people who care for you. It can be easy to forget that when you receive comments like that from other people. Those kids at your school are a small minority and their comments wouldn't be anything personal. They're the type of people who pick on people, just for the sake of it. 

Lastly, it's important to stay true to yourself. There is no normal way in how to "act" or behave in public. We are all individuals and we all have our own unique traits/values. If you are emotional and feel like crying, there's absolutely nothing wrong with that. Anyway, it's good to hear from you again. :) Take care.

That's just what you think, it's not reality. And even if it were the reality it would be dumb as hell for everyone in your school to think of you as weak just because you are a male crying and especially if it's for an actual good reason.

That doesn't make you weak, that just makes you different. Hell, I'm a girl yet don't even completely fit in with the female standards, doesn't make me any less of a girl than those who follow all of it. I'm still a girl regardless.
I feel as if you care too much about what others think. They probably aren't thinking of you like the way you think they are, and like I said before, it would be dumb as hell for them to even think that way. You are an emotional guy and there isn't anything wrong with that. Don't try and fit in with what society expects of you.

So it's not really about what others think, it's just that you're afraid to appear less like a man by crying in front of everyone, even though you had a good reason for it. You're basically doing what I just told you not to do in my last post that I responded to you. You're letting society define who you are and you're letting the gender stereotypes get to you. Society has brainwashed you into thinking that crying as a male is unmanly, which is far from the truth. You most likely feel this way because you aren't used to crying in front of everyone like that, as you mentioned you only feel comfortable crying in front of your dad. You always hide in your emotions and you've gotten used to that. Just because you hide in your feelings, doesn't mean you are strong. I'm not saying that you said this or anything, I'm just letting you know that's not the case. It's just false gender stereotypes, it's not the truth. Of course, expressing your feelings is easier said than done, but I'm just trying to let you know that crying is something everyone does. Like unicornic said it's healthy and natural to cry.