sad for no reason... :(

I will be 14 weeks in a few days and get to go in for my 2nd appointment where i should get to hear my babies heartbeat! My morning sickness was TERRIBLE from week 6-12 but for the last two weeks its been subsiding and I almost feel normal now. My SO is through the roof excited doing erything he can to make me as happy as possible. However I feel sad alllll the time. I want so badly to enjoy my pregnancy and be excited for this appointment but I feel like i dont have the energy to have those feelings :( not sure what to do I hope this passes.