My foundation is concrete. My plumbing isn't right?

I am also on a slab foundation. It could be tree roots have grown into your sewer line. I would call a licensed professional to assess the situation. For the wobbly toilets, it probably needs to be remounted, which means you need a new wax ring. And possibly new supply lines. This is something you can do yourself with help, toilets are heavy. Or have the plumber look at it.

In order to save on a plumber, youtube how to change a toilet and add the wax ring like Naomie suggests. if this doesn't work, then go to a plumber. I guarantee you the extra work could elimate a costly contractor. Also, if you recently redid your floors and laid them on top of the old one you may need a thicker wax ring depending on the depth of the new floor. If not, just a regular ring will do.

Slow drains may be one of several conditions: !. It could simply be that the sink drain[s] need to be cleaned out due to accumulation of hair in them [IF your sink stopper has a twist top on it- remove & use a flashlight to look inside to see if the drain is being clogged by hair. If it is, use a wire coat hanger with a slight hook formed on the end & push it beyond the clog of hair & pull it up. Run some water & see how well it drains...use the wire until the clog is gone & the water runs well] ...IF you don't have a twist top stopper, go under the sink & release the small metal tab that hold your stopper arm/rod in place, unscrew the cap that holds the arm in place & remove it [have a catch basin handy for any water seepage]. Go to the sink basin [above] & slowly lift the stopper & see if there is any debris/hair on the end of it-if so, clean it off. Take your flashlight & look down into the drain, Is there any debris? Can you remove it with a hook ended wire? If so, do so. If the drain is clear, REASSEMBLE the stopper BEFORE you run any water or you will end up with water under your sink. Periodically putting a couple tablespoons of Baking Soda into your drain & then adding about 1/2 cup of vinegar to it will help to clear greasy debris in drain pipes...but don't expect it to remove hair...it won't. Tub drains need to be cleared more often, use the wire to remove hair, use the soda-vinegar...flush with water after about 15 minutes. Do this before calling a plumber.

Toilets...wobbly means it's come loose from it's wax ring & OR the metal anchor bolts [found on the sides of the toilet at the base have come loose from their floor anchors], IF the anchors are loose, but the ring is okay:...using a pair of pliers...slowly move the anchor bolts until they 'grab ahold & won't pull up'...this IS a testing of patience! But it is worth in in the end...holding the bolt in position... tightened the nut down that is holding the anchor bolt...don't tighten too much or the toilet will crack/break; be sure to 're-anchor' both sides of the toilet. IF the toilet continues to leak after tightening the anchor bolts...you have a leaky wax ring & will have to dismantle the toilet from the floor[turn off the water, remove the water supply hose, remove all water, remove anchor bolts. remove tank lid, tilt the toilet forward & inspect the wax ring]. If the wax ring is damaged[you will see where it was leaking or there maybe a crease in the ring or where it didn't 'mesh' with the pipe], remove it, clean the excess wax from the toilet & pipe, using a hairdryer 'warm' the toilet where the ring is to go, warm the pipe & place the new wax ring onto the pipe, warm the wax ring, then set the toilet onto the new ring, pressing down until the base of the toilet meets the floor. Now patience is tested again...re-set the anchor bolts & cap them [if the caps fit-some don't], re-attach the water supply hose, turn on the water & replace the toilet lid, then sanitize the floor area. You are set! Make sure you periodically check that the anchor bolts are tight so you don't have this problem in the future.

Slow drains.... go to Dollar Tree, they usually have drain snakes to clean out hair and muck. Then put some Robiotic drain enzyme cleaner down there before you go to bed, and run hot water in morning. Repeat if not good.

You can get a replacement for the wax ring that will never leak and if you pot is wobbley use plastic spacers to shim it so it don't never use wood