What shoud I do?

Congrats on the job offer - I think you should take it! It sounds as if you need a new challenge and that there are no more opportunities with your present employer.

I think you are having a natural reaction of cold feet and nerves in regard to leaving the old and familiar and starting afresh.

You are obviously unhappy/unsettled/unfulfilled/unappreciated or unchallenged where you are and this is what made you look and apply for a new job to begin with.

You can keep in contact with those work colleagues who have now become friends. Don't stay because it is familiar; there are nice people and you are comfortable.

I say grab this opportunity with both hands and run with it.

When you do start your new job, remember it will be daunting the first few days/weeks. Hang in there.

I wish you oodles of luck.

Move forward and don't recind your resignation. You are just getting a little frightened at the new challenge ahead and are now afraid to leave the comfort of the familiar job and surroundings. There must have been a reason you resigned in the first place so just keep that in mind. Once you get used to the new job and the people there you will be fine.

You definitely need to make this move now. A lot of companies will not let you stay after you've let them know you're looking for a different job. They would question your loyalty and eventually push you out. This is a great opportunity, go for it.

Sometimes you have to stretch yourself to get ahead. There are better reasons for staying where you are than being "comfortable." If you are ambitious, you need to move on. especially while you are young and there are openings for you. In a few years, that situation could change and you will be stuck where you are.

Nothing ventured, nothing gained.

god will guide you.