I've been in a role I enjoy and find interesting/meaningful for almost 5 years. The work life balance is great and management is relaxed. However, there is no career progression, despite me taking on more and more responsibilities each year, and I'm worried I'm stagnating. I started on £40k and had one raise in this time to £42k (average-ish salary for the industry). Financially I'm comfortable, but only because I have a partner who earns similarly and we don't have kids (living in London). My manager isn't supportive and has basically told me to leave if I don't like it. (Essentially, if he's not getting a pay rise or promotion himself, he's not going to help me).
I've accepted a public sector job paying £52k (£600 more a month take home), plus excellent pension. Just waiting for reference checks. I should be delighted, and I am, but for some reason the thought of it is filling me with anxiety. It's going to be much faster paced and I'll be a line manager. I'm worried it will really stress me out. Is this normal? Should I listen to my gut and be grateful/stick with what I've got? I've also never handed in my notice before. I left my last job when my contract ended, previously I was freelance, and before that I was made redundant when my company folded.