It very well could be vaginismus. You can certainly get secondary vaginismus after having been fine previously. However, I also wonder if it could be that you are just still very sore and your cervix is quite irritated only being three days later. I wonder this mainly because you say you can get your vibrator and your fingers approximately three inches into your vagina. You may very well already know this but most vaginas are an average of 3 to 4 inches. It is possible that your cervix is still inflamed from all the activity and that is the wall you are touching that is painful. Vaginismus spasms tend to be closer to the entry of a vagina rather than deeper. That is why woman who do have vaginismus often can insert things much easier after they get past the muscles that are more shallow in the vagina. It is possible to have spasms deeper, though.
Please know that I am not at all discrediting your concern. I just really hate for you to jump to the conclusion that it is vaginismus this early on. I know it is hard not to worry ,though! I feel that giving it a few more days or so and resting will help you a lot. The fact that you can insert things is a great sign! Hopefully others will give you their advice and opinion as well.