How to deal with feeling hurt when he ignores me?

Ok, firstly, I don't know for sure that this guy will ignore me, but I predict/suspect this is what will happen…
Basically, I'm a college student, and on several occasions, my English professor (who is about 30, I'm early 20s) has flirted with me. The last time I saw him, however, instead of coming over and chatting as usual, he briefly said hi and hurried off. Yesterday, when he was sitting right next to me and another prof who were talking, he did not even acknowledge me, say hi or bye, just kept his eyes fixed on his phone/ipad…

There are a few occasions in the next semester when I'll have to be around him (once in a class, once at an event), and I think that, contrary to what he used to be like (i.e. Chatty, teasing me sometimes), he will just avoid me and ignore me… I understand that this is sensible on his part, as he can't be 'flirting' with a student, but, this will hurt (a lot) for me…

I've considered skipping the class he will give, and just completely blanking him too (other than an obligatory smile and 'hi' if I happen to come face to face with him), as a kind of 'coping mechanism'.

What can I do to cope with my hurt? Thanks, and I know lots of guys here will think I'm stupid, but…
Added (1). @Merlin - I didn't just 'dream up' flirty behaviour. I've explained some of his behaviours to my close friends, and they thought it sounded like flirting.

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