Normal?

Becky • Pregnant with my rainbow baby ❤️❤️❤️
Hi guys, I'm only 4 weeks 5 days but I've had the worst back ache today. It started this morning and it's just got worse as the days gone on. Anyone else experienced bad back ache this early on? I'm worried it means something is wrong. It's only my lower back. Thanks in advance ❤️