If i test negative for hiv three months after my last encounter, should i be fine? 3 months is the appropriate window period right?

That's up to you: Consider yourself healthy if it's one of the new-style tests that's essentially always positive by 3 months (actually quite a bit less). But you will be FINE when you become a mature lover, always loving safely out of respect for your own body and for the other person's. Don't put yourself or anyone else in situation like this again. Think ahead of the love with that one special lifetime person.