buds getting very heavy?

i have two plants inside a 4 gallon tub growing with a hydro system
the plants are just about done but all of the sudden the last week the plants started leaning over, i pretty much pushed the tub against the wall and have them leaning against the wall
im just wondering did the buds get bigger and i cant see that they did or did the buds just get heavier meaning filling in inside the bud?
i know its nothing bad im just curious does this happen usually?

idk man do you have pics ? your branches probly didnt get strong enuff to hold up the nugs

You can always use string to hold them up (don't use twine, that can cut the stems. you have to use string). Then the plant can use the string as support and focus more on bud production than working on strengthening the stem.

i actually am ready to harvest them i was more just wondering where the weight was coming from

Your plant decided to grow rocks instead of bud, maybe.