Grip problem

[Redvalic]

I have recently returned to playing golf after about a ten year break. I used to shoot around 75-80 but now I am haveing serious issues with mt grip on my backswing. I find that my right thumb is coming down in my backswing from its position near the shaft of the club, so much so i can feel it in my backswing. I notice this more on my woods than my irons but I feel I should not go any further until I remedy this issue. Have you guys had this happen before? I can usually work out my own kinks but I am not sure what the heck I am doing. Also, I am pull drawing the ball alot. I am probably coming over the top at times, but I didnt know if that would help any analysis.

Thanks