Hi Kelsey
Sorry to hear you are down after a good week. I think when you do have a good week, the low feeling seems even worse than when we are down all the time! The best bit though is that you now KNOW that you can have a good week and that will turn into weeks.
How to be strong enough to resist your ex? Well thats a hard call.
you know you are better off without him but as you say, the lonelyness makes us all very vunerable. Try to text him about his call so you dont actually speak, just say sorry to have missed your call, hope he is o.k and try to leave it at that. If you get to talk to him, you may just weaken.
you are doing so well. Hang on in there.
good luck