I have v brakes (really want disc but cant)and they are acting a little strange. I fixed my rear brakes but they seem a lot weaker than before!! How can I fix that? My front brakes are also screaching very loud when I even slightly tap them!!! WHats Wrong?

Need new brake pads??

I got this bike a weak ago and I need new pads!!!

That;s peculiar.

How often should i replace my break pads? I have ridden 3 times for about 2 hours each. one of the times I went through several inches of mud though. COuld that be it?

What bike is it? Was the rim wet when you tapped the brake?

Sounds to me like your brake pads need to be toed-in.

From parktool:
Pad Toeing
This is the setting of pad angle as it touches the rim. Toeing refers to setting the pad so the pad's front edge strikes first, which tends to reduce squeal during braking. Caliper arms tend to have play in the pivots and the arms flex when the brake is applied. This may cause squealing in the brake pads. It is simplest to first ride the bike and see if the brakes squeal.

Go here for complete instructions...

https://www.parktool.com/repair/readhowto.asp?id=21

Pad adjustment might help. For the squealing, toe the brakes a bit.

You shouldn't need new pads after three two hour rides. What you may need are decent pads. My Sequoia came with crappy pads that made all kinds of noise and didn't stop worth a darn. I replaced them with Kool Stops and problem solved. You may have picked up junk on the side of your rim as well. Try cleaning it with denatured alcohol (you can get it at Home Depot).

You "fixed my rear brake" and now it feels weak sounds like you need to tighten up the brake cable. You can try using the barrel adjuster to tighten it a bit. If that's not enough, undo the cable and pull it tighter before clamping it back down.

That is what I was going to say. A week of use, possibly cable stretch?

You might have sand or rocks stuck in the pads that make that loud noise.