could I be? just started TTC December

Ra
Hi, 
First post. Reading up on as much as I can just now. 
Our family so far= 
Myself, husband (5 months, 7years together) and our furbaby 🐶
Off the pill since September, and have just been busy working and saving some money last few months. Started TTC Dec. Ovulation dates according to this app were last week in December. Sex 5 days out of the 7. I was just educating mainly but I'm now convinced It's worked first try. Am I just being silly?
I have cramping in one side
Constipated
Sore head
Dizzy
Sore slightly swollen boobs
Really tender nipples
Tired
I'm not due period until 14th January so seems a bit early for period cramps. 
Desperate to test but I'm taking advice from other posts that if it ends up taking a while I will have spent a fortune that could otherwise buy baby bits and bobs. 
Mainly saying hi. But also am I likely to be being silly thinking that I'm pregnant. 
I will be a bit sad if I find out I'm not, but I know it's not usually this easy so also realistic. 
Sorry long post I need to learn all the abbreviations still.