Teething or 4 months spurt

Need help, so it’s my first baby and I don’t know what she has, she is usually so happy all the time and even when waking up just smiles. But it’s been 2 days that she cries a lot and it’s super irritating with everything. Too much salive since 1 month ago (she is 4 and a half) so I don’t know if it’s teething , or the famous 4 month spurt , she’s not drinking her milk so much , and cries and cries , and it breaks my heart but I want somebody to tell me it’s normal for babies at that age

Help 🥲