Anyone become pregnant while on the Depo shot and/or even though it took away your period!?

I ask because im scared that i may be pregnant. But what keeps convincing me that im not is that my symptoms started in November a few days after receiving my 4th Depo shot. Ive been getting them since Dec.07. I just received my portable mage table and as soon so i started bending over and putting it together my stomach became sore. Now ive been thinking about being pregnant for the past month so i feel like it could be that. Also the other day i had just waken up and while feeding my 14 month old he did something really cute and so i started laughing. I had slept on my stomach like most nights but i guess more the night before and my stomach felt sore. Now after i got the shot i started to get dizzy spells and feel really tired. Last month i started exercising but the past 2 week i have been feeling really tired and so i haven't exercised in a week. On about the 2nd or 3rd month of my first Depo shot i stopped getting my period. Ever since then ive had 2-3 times that i start to spot for like 3 days including the one that started 2 days ago. Im so confused but scared at the same time that i keep avoiding buying pregnancy tests! Including being really tired lately i feel like ive been lacking sleep even though ive been getting the same amount since ive been on vacation from school. Anytime i wake up now i feel so lazy and sleepy but i had already gotten use to getting less sleep in September last year when i start Mage Therapy cles. So my period stopping because of the Depo shot doesn't help me in figuring out if i could be pregnant or not. It's not like if my period didn't come i had a reason to suspect because the shot took it away! Please help and let me know what you think. I will be stopping by the store tomorrow after school to get some pregnancy test.